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Human Exposure and Atmospheric Sciences Division Publications: 2000

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This page lists publication titles, citations and abstracts produced by NERL's Human Exposure and Atmospheric Sciences Division for the year 2000, organized by Publication Type. Your search has returned 194 Matching Entries.

See also Human Exposure and Atmospheric Sciences Division citations with abstracts: 1999,  2000,  2001,  2002,  2003,  2004,  2005,  2006,  2007,  2008

Technical Information Manager: Liz Hope - (919) 541-2785 or hope.elizabeth@epa.gov
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Presented/Published
BOOK CHAPTER Field-Based Analysis of Organic Vapors in Air 01/01/2000
Berkley, R. E. Field-Based Analysis of Organic Vapors in Air. R.A Meyers (ed.), Encyclopedia of Analytical Chemistry. John Wiley & Sons, Ltd., Chichester, Uk, 3654-3672, (2000).
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
BOOK CHAPTER Analytical Challenges of Environmental Endocrine Disruptor Monitoring 01/01/2000
Van Emon, J. M., K. L. Bowman, AND C. L. Gerlach. Analytical Challenges of Environmental Endocrine Disruptor Monitoring. , Chapter 3, Analysis of Environmental Endocrine Disruptors. Oxford University Press, Cary, NC, 23-32, (2000).
Abstract: Reported increases in the incidence of endocrine-related conditions have led to speculation about environmental causes. Environmental scientists are focusing increased research effort into understanding the mechanisms by which endocrine disruptors affect human and ecological health. Fundamental to this understanding is the ability to characterize and quantify these types of chemical compounds. Immunoassays and tandem analytical techniques, that team chromatography with sensitive immunochemical methods, enable bioanalysis of compounds in complex matrices. Examples of immunochemical methods with applications to environmental monitoring and human exposure assessment are given.
BOOK CHAPTER Pesticides 12/31/2000
Lewis, R. G. Pesticides. , Chapter 35, John Spengler, Jonathan Samet, and John McCarthy (ed.), Indoor Air Quality Handbook. McGraw-Hill Companies, New York, NY, (2000).
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
JOURNAL Conceptual Basis for Multi-Route Intake Dose Modeling Using An Energy Expenditure Approach 01/01/2000
McCurdy, T. R. Conceptual Basis for Multi-Route Intake Dose Modeling Using An Energy Expenditure Approach. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 10(1):86-97, (2000).
Abstract: This paper provides the conceptual basis for a modeling logic that is currently being developed in the National Exposure Research Laboratory (NERL) of the U.S. Environmental Protection Agency ( EPA) for use in intake dose assessments involving substances that can enter the body via multiple routes of exposure. NERL is simultaneously developing a consolidated human activity database (hat will provide much of me data needed to parameterize equations used to implement the logic. EPA's Office of Air Quality Planning and Standards (OAQPS) is, in part, using the logic in its on - going review of the carbon monoxide national ambient air quality standard.
The information contained in this paper has been funded in part by teh U.S. Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
JOURNAL Correlations of Personal Exposure to Particles With Outdoor Air Measurement: A Review of Recent Studies 01/01/2000
Wallace, L. A. Correlations of Personal Exposure to Particles With Outdoor Air Measurement: A Review of Recent Studies. AEROSOL SCIENCE AND TECHNOLOGY 32(1):15-25, (2000).
Abstract: Epidemiological studies have found a correlation between daily mortality and particle concentrations in outdoor air as measured at a central monitoring station. These studies have been the central reason for the U.S. EPA to propose new tighter particle standards. However, personal monitoring studies have generally found very poor correlations (often approaching 0) between personal exposures and outdoor air concentrations. This has led to questions regarding the scientific basis of the new EPA standard. One reason for the poor correlations noted in the personal monitoring studies is that the correlations were cross-sectional: that is, they included many persons (generally monitored for only 1 or a few days) with no differentiation between persons exposed to high indoor sources (such as smokers) and those with much smaller exposures. Some recent studies have improved on this situation by following persons for a number of days and performing longitudinal correlations on individuals over time. These longitudinal correlations are almost invariably much higher than cross-sectional correlations. A second possible reason for the low correlations of personal exposure with outdoor concentrations is that most studies have been done on healthy-persons who may be much more active and therefore generate more particles than sick persons. Therefore a second set of studies has begun to be carried out looking at high-risk subpopulations, such as those with existing respiratory or cardiovascular disease.
A common element in these studies is the existence of a "personal cloud," an increased personal exposure beyond what is calculated from a time-weighted average of indoor and outdoor concentrations. The personal cloud for healthy persons can be quite sizable, on the order of 50 ug/m3 during the day when people are active and may be a major reason for the poor correlations of personal exposure with outdoor air concentrations. If the personal cloud of high-risk subpopulations is considerably smaller than that of healthy populations and if indoor sources are reduced in the impaired populations, then better correlations of personal exposure with outdoor air could be expected. Recent studies that have quantitated the personal cloud for both healthy and sick populations are reviewed.

Research described in this paper was carried out with partial funding from the U.S. Environmental Protection Agency. However, the views expressed in the article are not necessarily reflective of EPA policy. Mention of brand names or products is not to be construed as official endorsement.
JOURNAL Personal Exposure to Jp-8 Jet Fuel Vapors and Exhaust at Air Force Bases 03/01/2000
Pleil, J. D., L. B. Smith, AND S. D. Zelnick. Personal Exposure to Jp-8 Jet Fuel Vapors and Exhaust at Air Force Bases. ENVIRONMENTAL HEALTH PERSPECTIVES 108(3):183-192, (2000).
Abstract: JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 x the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective equipment that optimize risk reduction without undue impact on a mission.
This work was funded by the EPA and the U.S. Air Force. It has been subjected to EPA review and approved for publication. The views expressed here do not represent official views of the Department of Defense or the Department of the Air Force. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
JOURNAL Comparison of Scientific Findings from Major Ozone Field Studies in North America and Europe 03/01/2000
Solomon, P. A., E. Cowling, G. Hidy, AND C. Furiness. Comparison of Scientific Findings from Major Ozone Field Studies in North America and Europe. ATMOSPHERIC ENVIRONMENT 34(12-14):1885-1920, (2000).
Abstract: During the past decade, nearly 600 million dollars were invested in more than 30 major field studies in North America and Europe examining tropospheric ozone chemistry, meteorology, precursor emissions, and modeling. Most of these studies were undertaken to provide new or refined knowledge about ozone accumulation and to assist in the development of economical and effective emissions management practices for ozone. In this paper, we describe a selection of field research programs conducted under a wide range of geographical and climatological conditions in North America and Europe. The designs of these studies were generally similar, employing a combination of ground-based observation networks, upper-air sampling, and meteorological observations. Analysis and interpretation of the resulting data were combined with improved inventories of ozone precursor emissions and air quality modeling to develop new or enhanced knowledge about photochemical processes under various tropospheric conditions. The scientific results from these studies contained few surprises; in fact, they generally affirmed the conclusions in the review by the US National Research Council (NRC, 1999). Key findings include: (1) reaffirmation that tropospheric ozone is a multi-scale phenomenon extending to continental boundaries; (2) aerometric conditions aloft are important to ground-level ozone; (3) biogenic sources make important contributions to VOC and NO, emissions in parts of eastern North America and southern Europe; (4) emissions estimates are among the more uncertain components of predictive models for ozone; (5) recirculating flow over complex terrain and large water bodies are universally important factors affecting accumulation of ozone at the ground; (6) nonlinearities in ozone response to precursor changes create important degrees of freedom in management strategies - VOC and NO., sensitivities vary extensively in urban and rural areas, making decisions about emissions management complicated; (7) measurement methods for many precursors, intermediates, and products of photochemical reactions have improved greatly; and (8) additional analysis and interpretation of existing data from many of these field studies should pay handsome dividends at relatively modest cost.
The U.S. Environmental Protection Agency through its Office of Research and Development collaborated in the research described here. This manuscript has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement of recommendation for use.
JOURNAL Guidance for the Performance Evaluation of Three-Dimensional Air Quality Modeling Systems for Particulate Matter and Visibility 04/01/2000
Seigneur, C., B. Pun, P. Pai, J. Louis, P. A. Solomon, C. Emery, R. Morris, M. S. Zahniser, D. R. Worsnop, P. Koutrakis, W. White, AND I. Tombach. Guidance for the Performance Evaluation of Three-Dimensional Air Quality Modeling Systems for Particulate Matter and Visibility. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION 50(4):588-599, (2000).
Abstract: The National Ambient Air Quality Standards for particulate matter (PM) and the federal regional haze regulations place some emphasis on the assessment of fine particle (PM; 5) concentrations. Current air quality models need to be improved and evaluated against observations to assess the reliability of model simulations. The guidance presented here provides the necessary framework for conducting rigorous performance evaluations of PM and visibility models. The costs associated with the Field programs needed to obtain the data necessary for such performance evaluations are estimated to be $15 million for data collection (1 -year program with an intensive program of 15 days, over 200,000 km2) and $10-$20 million for planning, emission inventories, data analysis, and modeling.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development, colloborated in the research described here. It has been subjected to EPA review and approved for publication. Mention of trade names of commercial products does not constitute an endorsement or recommendation for use.
JOURNAL Emissions from Two Outboard Engines Operating on Reformulated Gasoline Containing Mtbe 02/01/2000
Gabele, P. A. AND S. M. Pyle. Emissions from Two Outboard Engines Operating on Reformulated Gasoline Containing Mtbe. ENVIRONMENTAL SCIENCE & TECHNOLOGY 34(3):368-372, (2000).
Abstract: Air and water pollutant emissions were measured from two 9.9 HP outboard engines: a two-stroke Evinrude and its four-stroke Honda counterpart. In addition to the measurement of regulated air pollutants, speciated organic pollutants and particulate matter emissions were determined. Aqueous samples were analyzed for MTBE (methyl tert-butyl ether) and BTEX (benzene, toluene, ethyl-benzene, and xylene) emission rates. Compared to the four-stroke engine, the two-stroke had dramatically higher levels of toxic organic and particulate matter emissions. The organic material emitted from the two-stroke engine resembles the test gasoline due to the predominance of unburned fuel. Emission rates for PM10 (particulate matter with a diameter of 10 mm or less) are equal to those for PM2.5 , implying that emitted particles are all in the respirable range. Aqueous emissions from the two-stroke are also higher: the two-stroke's BTEX and MTBE emissions are, on average, 5 and 24 times higher, respectively, and 3-10 percent of the MTBE fed to the engine is emitted to the water. Aqueous emission rates, expressed in brake-specific units, tend to increase with decreasing engine load, as do the atmospheric emission rates.
The information in this paper has been funded by the Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
JOURNAL Indoor and Outdoor PM10 and Associated Metals and Pesticides in Arizona 06/10/2000
Lebowitz, M. D., M. K. O'Rourke, S. Rogan, J. Reses, P. Van de Water, A. Blackwell, D. J. Moschandreas, S. M. Gordon, AND G. L. Robertson. Indoor and Outdoor PM10 and Associated Metals and Pesticides in Arizona. INHALATION TOXICOLOGY 12(Sup 1):139-144, (2000).
Abstract: The National Human Exposure Assessment Survey study in Arizona (AZ NHEXAS) sampled trace metals in multimedia in and outside of 176 representative homes in Arizona. PM10 was collected using low-flow impactors indoors and out. Primary metals evaluated from monitoring of indoor and outdoor air were lead, cadmium, chromium, nickel, and arsenic. Secondary metals were also evaluated. They were analyzed using gas chromatography-inductively coupled plasma/atomic emission spectroscopy (GC-ICP/AES). Air concentrations of metals do not contribute appreciable amounts to total concentrations of metals, and none were above levels of concern. Measurements were made of selected pesticides (primarily chlorpyrifos and diazinon) from particulate matter (PM10) filters obtained indoors and outdoors. Indoor air pesticide exposures represent about 25% of the total exposure to these pesticides. The highest 10% of exposures were related to questions about pesticide usage, at home and at work.
The U.S. Environmenal Protection Agency through its Office of Research and Development funded and collaborated in the research described here under cooperative agreement CR821560 and contact 68-D-99-002 to Michael D. Lebowitz. This article has been subjected to agency review and approved for publication. Mention of trade names or commercial products does not constitutute an endorsement or recommendation for use.
JOURNAL Ozone Uptake in the Intact Human Respiratory Tract Relationship Between Inhaled and Actual Dose 06/01/2000
Rigas, M. L., S. N. Catlin, A. BenJebria, AND J. S. Ultman. Ozone Uptake in the Intact Human Respiratory Tract Relationship Between Inhaled and Actual Dose. JOURNAL OF APPLIED PHYSIOLOGY 88(6):2015-2022, (2000).
Abstract: Inhaled concentration (C), minute volume (MV), and exposure duration (T) are factors that may affect the uptake of ozone (03) within the respiratory tract. Ten healthy adult nonsmokers participated in four sessions, inhaling 0.2 or 0.4 ppm 03 through an oral mask while exercising continuously to elicit a MV of 201/min for 60 min or 401/min for 30 min. In each session, fractional absorption (FA) was determined on a breath-by-breath basis as the ratio of O3 uptake to the inhaled 03 dose. The mean plus/minus SD value of FA for all breaths was 0.86 plus/minus 0.06. Although C, MV, and T all had statistically significant effects on FA (P < 0.0001, P = 0.004, and P = 0.026, respectively), the magnitudes of these effects were small compared with intersubject variability. For an average subject, a 0.05 change in FA would require that C change by 1.3 ppm, MV change by 46 1/min, or T change by 1.7 h. It is concluded that inhaled dose is a reasonable surrogate for the actual dose delivered to a particular subject during 03 exposures of <2 h, but it is not a reasonable surrogate when comparisons are made between individuals.
The U.S. Environmental Protection Agency through its Office of Research and Development collaborated in the research described here. This research has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use. This work has been partially funded by National Institute of Environmental Health Sciences research grant R01 ES-06075. Clinical support was provided by the General Clinical Research Center of the Pennsylvania State University through funding by National Center for Research Resources grant M01 RR-10732.
JOURNAL Design Strategy for Assessing Multi-Pathway Exposure for Children: the Minnesota Children's Pesticide Exposure Study (Mncpes) 03/01/2000
Quackenboss, J. J., E. D. Pellizzari, P. Shubat, R. W. Whitmore, J. L. Adgate, K. W. Thomas, N. G. Freeman, C. Stroebel, P. J. Lioy, C. A. Clayton, AND K. G. Sexton. Design Strategy for Assessing Multi-Pathway Exposure for Children: the Minnesota Children's Pesticide Exposure Study (Mncpes). JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 10(2):145-158, (2000).
Abstract: Although children are exposed to a variety of environmental hazards, including pesticides, there is a scarcity of information available to estimate exposures realistically. This article reports on one of the first attempts to measure multi-pathway pesticide exposures in a population-based sample of urban and non-urban children. A design strategy was developed to assess multi-pathway pesticide exposures in children using personal exposure measurements in combination with complimentary measurements of biological markers of exposure, concentrations in relevant environmental media, and time spent in important microenvironments and participating in exposure-related activities. Sample collection and analysis emphasized measurement of three insecticides (i.e., chlorpyrifos, diazinon, and malathion) and one herbicide (i.e., atrazine). These compounds were selected because of their frequent use, presence in multiple environmental media, expected population exposures, and related hazard/toxicity. The study was conducted during the summer of 1997 in Minnesota and involved a stratified sample of households with children ages 3-12 years. Participants resided in either (a) the cities of Minneapolis and St. Paul (urban households), or (b) Rice and Goodhue Counties just south of the metropolitan area (non-urban households). Results from a residential inventory documenting storage and use of products containing the target pesticides were used to preferentially select households where children were likely to have higher exposures. The study successfully obtained pesticide exposure data fro 102 children, including measurements of personal exposures (air, hand rinse, duplicate diet), environmental concentrations (residential indoor/outdoor air, drinking water, residential surfaces, soil), activity patterns (obtained by questionnaire, diary, videotaping), and internal dose (metabolites in urine).
JOURNAL Stability of Hemoglobin and Albumin Adducts of Benzene Oxide and 1,4-Benzoquinone After Administration of Benzene to F344 Rats 03/01/2000
Troester, M. A., A. B. Lindstrom, L. L. Kupper, S. Waidyanatha, AND S. M. Rappaport. Stability of Hemoglobin and Albumin Adducts of Benzene Oxide and 1,4-Benzoquinone After Administration of Benzene to F344 Rats. TOXICOLOGICAL SCIENCES 54(1):88-94, (2000).
Abstract: The stability of cysteinyl adducts of benzene oxide (BO) and mono-S-substituted cysteinyl adducts of 1,4-benzoquinone (1,4-BQ) was investigated in both hemoglobin (Hb) and albumin (Alb) following administration of a single oral dose of 400 mg [U-14C/13C6]benzene/kg body weight to F344 rats. Total radiobound adducts to Hb were stable, as were adducts formed by the reaction of [13C6]BO with cysteinyl residues on Hb. In both cases adduct stability was indicated by zero-order kinetics with decay rates consistent with the lifetime of rat erythrocytes. Hb adducts of 1,4-BQ were not detected, possibly due to the production of multi-S-substituted adducts within the erythrocyte. Regarding the Alb binding, total radiobound adducts decayed more rapidly than expected )half-life of 0.4 days), suggesting that uncharacterized benzene metabolites were noncovalently bound or formed unstable adducts with Alb. Although adducts from reactions of BO and 1,4-BQ with Alb both decayed with rates consistent with those of Alb turnover in the rat, the half-life for 1,4-BQ-Alb (2.5 days) was shorter than that for BO-Alb (3.1 days), suggesting some instability of 1,4-BQ-Alb. Assuming similar rates of adduct instability in humans and rats, the 1,4-BQ-Alb adducts would be eliminated with a half-life of approximately 8 days, compared with BO-Alb, which would be expected to turnover with Alb (half-life of approximately 21 days).
This work was supported by the National Institute of Environmental Health Sciences through grant P42ES05948 and training grant 5-T32-ES07018. The work described in this document has been funded in part by the U.S. Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
JOURNAL Capillary Electrophoresis Immunoassay for 2,4-Dichlorophenoxyacetic Acid 01/31/2000
Rogers, K. R., A. B. Apostol, AND W. C. Brumley. Capillary Electrophoresis Immunoassay for 2,4-Dichlorophenoxyacetic Acid. ANALYTICAL LETTERS 33(3):443-453, (2000).
Abstract: A capillary electrophoresis (CE) immunoassay format for 2,4-dichlorophenoxyacetic acid (2,4-D) is demonstrated. A fluorescent labeled 2,4-D analog competes with the analyte of interest for a finite number of binding sites provided by anti-2,4-D monoclonal antibodies. CE then provides a means of separating and measuring both the free and antibody-bound fluorescent tracer using laser-induced fluorescence detection. For this assay format, the amount of free tracer is a sensitive indicator for the concentration of analyte present in the sample. A sequential injection format allows the rapid analysis of a small number of samples. The dynamic concentration range for 2,4-D in either buffer or river water is 5 ppb to 1000 ppb.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded the work involved in preparing this article. It has been subject to the Agency's peer review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by the U.S. EPA.
JOURNAL Temporal Variability in the Basal Isoprene Emission Factor 06/01/2000
Geron*, C. D., A. Guenther, T. D. Sharkey, AND R. R. Arnts. Temporal Variability in the Basal Isoprene Emission Factor. TREE PHYSIOLOGY 20(12):799-805, (2000).
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
JOURNAL Principles of Affinity-Based Biosensors 06/13/2000
Rogers, K. R. Principles of Affinity-Based Biosensors. MOLECULAR BIOTECHNOLOGY 14(2):109-129, (2000).
Abstract: Despite the amount of resources that have been invested by national and international academic, government, and commercial sectors to develop affinity-based biosensor products, little obvious success has been realized through commercialization of these devices for specific applications (such as the enzyme biosensors for blood glucose analysis). Nevertheless, the fastest growing area in the biosensors research literature continues to involve advances in affinity-based biosensors and biosensors and biosensor-related methods. Numerous biosensor techniques have been reported that allow researchers to better study the kinetics, structure, and (solid/liquid) interface phenomena associated with protein-ligand binding interactions. In addition, potential application areas for which affinity-based biosensor techniques show promise include clinical/diagonstics, food processing, military/antiterrorism, and environmental monitoring. The design and structural features of these devices-composed of a biological affinity element interfaced to a signal transducer-primarily determine their operational characteristics. This paper, although not intended as comprehensive review, will outline the principles of affinity biosensors with respect to potential application areas.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD) has, in part, funded the work involved in preparing this article. It has been subject to the Agency's peer review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by EPA. The U.S. Government has the right to retain a non-exclusive, royalty-free license in and to any copyright covering this article.
JOURNAL Associations Between Air Pollution and Mortality in Phoenix, 1995-1997 04/01/2000
Mar, T. F., G. A. Norris, J. Q. Koenig, AND T. V. Larson. Associations Between Air Pollution and Mortality in Phoenix, 1995-1997. ENVIRONMENTAL HEALTH PERSPECTIVES 108(4):347-353, (2000).
Abstract: We evaluated the association between mortality outcomes in elderly individuals and particulate matter (PM) of varying aerodynamic diameters (in micrometers) [PM10, PM2.5, and PMCF (PM10 minus PM2.5)], and selected particulate and gaseous phase pollutants in Phoenix, Arizona, using 3 years of daily data (1995-1997). Although source apportionment and epidemiologic methods have been previously combined to investigate the effects of air pollution on mortality, this is the first study to use detailed PM composition data in a time-series analysis of mortality. Phoenix is in the arid Southwest and has approximately 1 million residents (9.7% of the residents are > 65 years of age). PM data were obtained from the U.S.Environmental Protection Agency (EPA) National Exposure Research Laboratory Platform in central Phoenix. We obtained gaseous pollutant data, specifically carbon monoxide, nitrogen dioxide, ozone, and sulfur dioxide data, from the EPA Aerometric Information Retrieval SystemDatabase. We used Poisson regression analysis to evaluate the associations between air pollution and nonaccidental mortality and cardiovascular mortality. Total mortality was significantly associated with CO and NO2 (p < 0.05) and weakly associated with
SO2, PM10, and PMCF (p < 0.10). Cardiovascular mortality was significantly associated with CO, NO2, SO2, PM2.5, PM10, PMCF (p < 0.05), and elemental carbon. Factor analysis revealed that both combustion-related pollutants and secondary aerosols (sulfates) were associated with cardiovascular mortality. Key words: cardiovascular, composition, factor analysis, particulate matter, PM2.5, PM10, sources.

This publication was made possible in part by grant 5T32 ES07262 from the NIEHS, NIH. The U.S. EPA Office of Research and Development partially funded and collaborated in the research described here under assistance agreement R827355 to the University of Washington. The contents of this paper are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH. This paper has been subjected to EPA review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
JOURNAL Children's Exposure Assessment: A Review of Factors Influencing Children's Exposure and the Data Available to Characterize and Assess That Exposure 06/01/2000
CohenHubal, E. A., V. Zartarian, L. S. Sheldon, T. R. McCurdy, M. L. Rigas, M. R. Berry Jr., J. M. Burke, AND N. G. Freeman. Children's Exposure Assessment: A Review of Factors Influencing Children's Exposure and the Data Available to Characterize and Assess That Exposure. ENVIRONMENTAL HEALTH PERSPECTIVES 108(6):475-486, (2000).
Abstract: We review the factors influencing children's exposure to environmental contaminants and the data available to characterize and assess that exposure. Children's activity pattern data requirements are demonstrated in the context of the algorithms used to estimate exposure by inhalation, dermal contact, and ingestion. Currently, data on children's exposures and activities are insufficient to adequately assess multimedia exposures to environmental contaminants. As a result, regulators use a series of default assumptions and exposure factors when conducting exposure assessments. Data to reduce uncertainty in the assumptions and exposure estimates are needed to ensure chemicals are regulated appropriately to protect children's health. To improve the database, advancement in the following general areas of research is required: identification of appropriate age/developmental benchmarks for categorizing children in exposure assessment; development and improvement of methods for monitoring children's exposures and activities; collection of activity pattern data for children (especially young children) required to assess exposure by all routes; collection of data on concentrations of environmental contaminants, biomarkers, and transfer coefficients that can be used as inputs to aggregate exposure models.
This paper has been reviewed in accordance with the U.S. EPA peer and administrative review policies and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
JOURNAL An Automated System for Producing Uniform Surface Deposits of Dry Particles 10/01/2000
Antley, J. T., R. W. Vanderpool, AND S. L. Harper. An Automated System for Producing Uniform Surface Deposits of Dry Particles. AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL 61(5):669-677, (2000).
Abstract: A laboratory system has been constructed that uniformly deposits dry particles onto any type of test surface. Devised as a quality assurance tool for the purpose of evaluating surface sampling methods for lead, it also may be used to generate test surfaces for any contaminant that uses particles or dust as a transport mechanism. Additionally, it may be used to spike surfaces for studies concerning particle transport, resuspension, reentrainment, and exposure. The electromechanical system includes a rugged aluminum chamber housing deposition equipment, a computer-controlled positioning system, and a 0.61 X 0.61 m target surface area (2 X 2 ft). Media used to evaluate the system have included glass beads of various size fractions (physical diameters between 30 and 500 um), and Arizona Test Dust (aerodynamic diameters between 1 and 80 um). Presieved particle size fractions may be used individually to study the effects of monodisperse particles, or may be mixed to create custom polydisperse size distributions. Using arrays of 16 coupons placed on the surface to collect representative samples from every test, the uniformity of the particle deposition can be quantified. The system achieved an average coefficient of variation of less than 20% for the 16 coupons for theparticle types and sizes mentioned above and for a variety of total surface loadings (0.3-19 g/m2). Calculations of the system's repeatability (as the average coefficient of variation of mass gains for individual coupon locations compared across multiple identically configured runs) yielded approximately 10 plus/minus 5% (one standard deviation). Tests of the system's accuracy, defined as the absolute percentage difference between predicted surface loadings and actual loadings, yielded 3.7 plus/minus 1.3% (one standard deviation).

The information present in this paper has been wholly funded by the United States Environmental Protection Agency's (EPA's) National Exposure Research Laboratory under contract 68-D5-0040. It has been subjected to EPA review and approved. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
JOURNAL Interpolating Vancouver's Daily Ambient PM 10 Field 11/01/2000
Sun, L., J. Zidek, N. D. Le, AND A. H. Ozkaynak. Interpolating Vancouver's Daily Ambient PM 10 Field. ENVIRONMETRICS 11(6):651-663, (2000).
Abstract: In this article we develop a spatial predictive distribution for the ambient space- time response field of daily ambient PM10 in Vancouver, Canada. Observed responses have a consistent temporal pattern from one monitoring site to the next. We exploit this feature of the field by adopting a response model with two components, a common deterministic trend across all sites plus a stochastic residual. We are thereby able to whiten the temporal residuals without losing much of the spatial correlation in the original log transformed series. This in turn enables us to develop an effective spatial predictive distribution for these residuals at unmonitored sites. By transforming the predicted residuals back to the original data scales we can impute Vancouver's daily PM10 field for purposes such as human exposure and health impacts analysis.
The U.S. Environmental Protection Agency through its Office of Research and Development partially funded the research described here under a Cooperative Agreement #CR825267-01 to Harvard University School of Public Health. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
JOURNAL Improved Selective Electrocatalytic Oxidation of Phenols By Tyrosinase-Based Carbon Paste Electrode Biosensor 11/16/2000
Rogers, K. R., J. Y. Becker, AND J. Cembrano. Improved Selective Electrocatalytic Oxidation of Phenols By Tyrosinase-Based Carbon Paste Electrode Biosensor. ELECTROCHIMICA ACTA 45(25-26):4373-4379, (2000).
Abstract: Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil yielded a greater response to phenol and catechol than those using a higher viscosity oil of similar chemical composition. Despite its relatively high viscosity, the use of silicon oil Si PS 086 as carbon paste binder resulted in a 2-fold increase over Si AR 200 and a 4?6 fold increase (over mineral oils) in responses to phenol, p-chlorophenol, and p-cresol. Also reported is the enhanced enzyme electrode response to phenol and catechol resulting from pre-oxidation of these substrates using a plain carbon paste electrode in a series (in-line) dual electrode configuration.
The US Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded this research. It has been subject to the EPA's peer and administrative review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by EPA for use.
JOURNAL A Modeling Framework for Estimating Children's Residential Exposure and Dose to Chlorpyrifos Via Dermal Residue Contact and Non-Dietary Ingestion 06/01/2000
Zartarian, V., A. H. Ozkaynak, J. M. Burke, M. J. Zufall, M. L. Rigas, AND E. J. Furtaw Jr. A Modeling Framework for Estimating Children's Residential Exposure and Dose to Chlorpyrifos Via Dermal Residue Contact and Non-Dietary Ingestion. ENVIRONMENTAL HEALTH PERSPECTIVES 108(6):505-514, (2000).
Abstract: To help address the Food Quality Protection Act of 1996, a physically-based probabilistic model (Residential Stochastic Human Exposure and Dose Simulation Model for Pesticides; Residential-SHEDS) has been developed to quantify and analyze dermal and non-dietary ingestion exposure and dose to pesticides. The model simulates children contacting residues on surfaces in treated residences and turf in treated residential yards by combining sequential time-location-activity information from children's diaries with micro-level videotaped activity data, probability distributions of measured surface residues and exposure factors, and pharmacokinetic rate constants. Model outputs include individual profiles and population statistics for daily dermal loading, mass in the blood compartment, ingested residue via non-dietary objects, and mass of eliminated metabolite, as well as contributions from various routes, pathways, and media.
To illustrate the capabilities of the model framework, Residential-SHEDS was applied to estimate children's residential exposure and dose to chlorpyrifos for 12 exposure scenarios: 2 age groups (0 to 4 years, 5 to 9 years); 2 indoor pesticide application methods (broadcast, crack and crevice); and 3 post-indoor application time periods (<1 day, 1 to 7 days, 8 to 30 days). Independent residential turf applications (liquid or granular) were included in each of these scenarios. Despite the current data limitations and model assumptions, the case study predicts exposure and dose estimates that compare well to measurements in the published literature, and provides insights to the relative importance of exposure scenarios and pathways.

This paper has been reviewed in accordance with the U.S. Environmental Protection Agency peer and administrative review policies and approved for publication. Mention of trade names and commercial products does not constitute endorsement or recommendation for use.
JOURNAL PAH Exposures of Nine Preschool Children 01/01/2000
Wilson, N. K., J. C. Chuang, AND C. Lyu. PAH Exposures of Nine Preschool Children. POLYCYCLIC AROMATIC COMPOUNDS 21(3):247-259, (2000).
Abstract: The exposures to 20 polycyclic aromatic hydrocarbons (PAH) of 9 children, ages 2-5 yr, were measured over 48 hr at day care and at home. Sampled media included indoor and outdoor air, floor dust, outdoor play area soil, hand surface, and solid and liquid food. Urine samples were collected for metabolite analysis. Diaries of the children's activities during the sampling period were also kept.
Significant positive correlations between media were found for total PAH in indoor air with floor dust (p<0.001), and for total PAH in outdoor air with floor dust (p<0.05). Also at the p<0.05 level, the B2 PAH (probable human carcinogens) were correlated in play area soil with outdoor air, and in outdoor with indoor air. Total PAH and B2 concentrations were correlated in play area soil and in floor dust (p<0.05).

The relative importance of the exposure pathways differed for total PAH and B2 PAH. For total PAH, which included both volatile and semi-volatile compounds, inhalation was most important, then dietary ingestion, then non-dietary ingestion. In contrast, for the B2 PAH only, non-dietary ingestion was most important, then dietary ingestion, and inhalation was least important.

Differences in the children's PAH exposures were small between day care and home, and also between children from low-income and from middle-income families.

The information in this document has been funded wholly or in part by the United States Environmental Protection Agency under Contract 68-D4-0023 to Battelle. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
JOURNAL Comparison of the Octanol-Air Partition Coefficient and Liquid-Phase Vapor Pressure as Descriptors for Particle/Gas Partitioning Using Laboratory and Field Data for PCBs and Pcns 06/01/2000
Falconer, R. L. AND T. Harner. Comparison of the Octanol-Air Partition Coefficient and Liquid-Phase Vapor Pressure as Descriptors for Particle/Gas Partitioning Using Laboratory and Field Data for PCBs and Pcns. ATMOSPHERIC ENVIRONMENT 34(23):4043-4046, (2000).
Abstract: The conventional Junge-Pankow adsorption model uses the sub-cooled liquid vapor pressure (pLo) as a correlation parameter for gas/particle interactions. An alternative is the octanol-air partition coefficient (Koa) absorption model. Log-log plots of the particle-gas partition coefficient versus pLo were previously made for partitioning data from controlled laboratory studies, resulting in separate trend lines for different ortho-substituted PCB classes. The same plots applied to field data for PCBs and PCNs resulted in separate regression lines with slopes that were statistically different at the 99% confidence level. When Koa is used as the correlation parameter, these differences are resolved showing the ability of the model to reduce variability both within a compound class and between compound classes. The Koa model is also preferred because it uses parameters that can be measured directly (Koa and fom), unlike the parameters of the Junge-Pankow model which must be estimated.
The research described herein was developed by the author, an employee of the US Environmental Protection Agency, in her previous position. It was conducted independently of EPA employment and has not been subjected to Agency's peer and administrative review. Therefore, the conclusions and opinions drawn are solely those of the author and should not be construed to reflect the views of the Agency.
JOURNAL Indoor, Outdoor, and Personal Exposure Monitoring of Particulate Air Pollution: the Baltimore Elderly Epidemiology-Exposure Pilot Study 08/01/2000
Williams, R. W., J. P. Creason, R. B. Zweidinger, R. R. Watts, L. S. Sheldon, AND C. M. Shy. Indoor, Outdoor, and Personal Exposure Monitoring of Particulate Air Pollution: the Baltimore Elderly Epidemiology-Exposure Pilot Study. ATMOSPHERIC ENVIRONMENT 34(24):4193-4204, (2000).
Abstract: A 17-day pilot study investigating potential PM exposures of an elderly population was conducted near Baltimore, Maryland. Collection of residential indoor, residential outdoor, and ambient monitoring data associated with the subjects living at a common retirement facility was integrated with results from a paired epidemiological pilot study. This integration was used to investigate the potential pathophysiological health effects resulting from daily changes in estimated PM exposures with results reported elsewhere. Objectives of the exposure study were to determine the feasibility of performing PM exposure assessment upon an elderly population and establishing relationships between the various exposure measures including personal monitoring. PM2.5 was determined to be the dominant outdoor size fraction (0.83 PM2.5 /PM10 mass ratio by dichot monitoring). Individual 24-hr PM1.5 personal exposures ranged from 12 to 58 ?g m-3. Comparison of data from matched sampling dates resulted in mean daily PM1.5 personal, PM2.5 outdoor, and PM1.5 indoor concentrations of 34, 17, and 17 ug m-3, respectively. Activity patterns of the study population indicated a generally sedentary population spending a mean of 96% of each day indoors. Future studies would benefit from the use of a consistent sampling methodology across a larger number of PM measurement sites relevant to the elderly subjects, as well as a larger personal PM exposure study population to more successfully collect data needed in matched epidemiological-exposure studies.
The US Environmental Protection Agency through its Office of Research and Development conducted the research described here. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not consitutue endorsement or recommendation for use.
JOURNAL Real-Time and Integrated Measurement of Potential Human Exposure to Particle-Bound Polycyclic Aromatic Hydrocarbons (PAHs) from Aircraft Exhaust 09/01/2000
Childers, J. W., C. L. Witherspoon, L. B. Smith, AND J. D. Pleil. Real-Time and Integrated Measurement of Potential Human Exposure to Particle-Bound Polycyclic Aromatic Hydrocarbons (PAHs) from Aircraft Exhaust. ENVIRONMENTAL HEALTH PERSPECTIVES 108(9):853-862, (2000).
Abstract: Real-time monitors and low-volume air samplers were used to measure the potential human exposure to airborne polycyclic aromatic hydrocarbon (PAH) concentrations during various flight-related and ground-support activities of C-130H aircraft at an Air National Guard base. Three types of photoelectric aerosol sensors (PASs) were used to measure real-time concentrations of particle-bound PAHs in a break room, downwind from a C-130H aircraft during a four-engine run-up test, in a maintenance hangar, in a C-130H aircraft cargo bay during cargo-drop training, downwind from aerospace ground equipment (AGE), and in a C-130H aircraft cargo bay during engine running on/off (ERO) loading and backup exercises. Two low-volume air samplers were collocated with the real-time monitors for all monitoring events except those in the break room and during in-flight activities. Total PAH concentrations in the integrated-air samples followed a general trend: downwind from two AGE units > ERO-loading exercise > four-engine run-up test > maintenance hangar during taxi and takeoff > background measurements in maintenance hangar. Each PAH profile was dominated by naphthalene, the alkyl-substituted naphthalenes, and other PAHs expected to be in the vapor phase. Particle-bound PAHs, such as fluoranthene, pyrene, and benzo[a]pyrene, were also detected in some of the sample extracts. During flight-related exercises, total PAH concentrations in the integrated-air samples were 10?25 times higher than those commonly found in ambient air. Real-time monitor mean responses generally followed the integrated-air sample trends. These monitors provided a semi-quantitative temporal profile of ambient PAH concentrations and showed that PAH concentrations can fluctuate rapidly from a baseline level below 20 ng m-3 to > 4,000 ng m-3 during flight-related activities. Small handheld models of the PAS monitors exhibited potential for assessing incidental personal exposure to particle-bound PAHs in engine exhaust and for serving as a real-time dosimeter to indicate when respiratory protection is advisable.
This abstract has been subjected to Agency review and approved for publication.
JOURNAL The Challenge of Assessing Children's Exposure to Pesticides 01/01/2000
CohenHubal, E. A., L. S. Sheldon, M. J. Zufall, J. M. Burke, AND K. W. Thomas. The Challenge of Assessing Children's Exposure to Pesticides. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 10(S6):638-649, (2000).
Abstract: In implementing the Food Quality Protection Act (FQPA) the U.S. Environmental Protection Agency (USEPA) has adopted a policy that the exposure factors and models used to assess and predict exposure to pesticides should generally be conservative. Some elements of exposure assessments for FQPA are screening level they are both uncertain and conservative. If more realistic assessments are to be conducted, then research is required to reduce uncertainty associated with the factors and models used in the exposure assessments. To develop the strategy for conducting this research, critical exposure pathways and factors were identified, and the quality and quantity of data associated with default assumptions for exposure factors were evaluated. Then, based on our current understanding of the pathways that are potentially most important and most uncertain, significant research requirements were identified and prioritized to improve the data available and assumptions used to assess children's aggregate exposure to pesticides. Based on the results of these efforts, four priority research areas were identified: (1) pesticide use patterns in microenvironments where children spend time, (2) temporal and spatial distribution of pesticides following application in a residential setting, (3) dermal and nondietary ingestion exposure assessment methods and exposure factors, (4) dietary exposure assessment methods and exposure factors for infants and young children. The National Exposure Research Laboratory (NERL) research strategy in support of FQPA is designed to address these priority research needs.
This paper has been reviewed in accordance with the US EPA's peer and administrative review policies and approved for publication. Mention of trade names or commercial products does not consitutute endorsement or recommendation for use.
JOURNAL Use of a Continuous Nephelometer to Measure Personal Exposure to Particles During the U.S. EPA Baltimore and Fresno Panel Studies 07/01/2000
HowardReed, C., A. W. Rea, M. J. Zufall, J. M. Burke, R. W. Williams, J. C. Suggs, L. S. Sheldon, D. B. Walsh, AND R. K. Kwok. Use of a Continuous Nephelometer to Measure Personal Exposure to Particles During the U.S. EPA Baltimore and Fresno Panel Studies. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION 50(7):1125-1132, (2000).
Abstract: In population exposure studies, personal exposure to particulate matter (PM) is typically measured as a 12- to 24-hour integrated mass concentration. To better understand short-term variation in personal PM exposure, continuous (one-minute averaging time) nephelometers were worn by 15 participants as part of two U.S. Environmental Protection Agency(U.S. EPA) longitudinal PM exposure studies conducted in Baltimore County, Maryland and Fresno, California. Participants also wore inertial impactor samplers (24-hour integrated filter samples) and recorded their daily activities in 15 minute intervals. In Baltimore, the nephelometers correlated well (R2= 0.66) with the PM2.5 impactors. Time-series plots of personal nephelometer data showed each participant's PM exposure to consist of a series of peaks of relatively short duration. Activities corresponding to a significant instrument response included cooking, outdoor activities, transportation, laundry, cleaning, shopping, gardening, moving between microenvironments, and removing/putting on the instrument. On average 63% - 66% of the daily PM exposure occurred indoors at home (about 2/3 of which occurred during waking hours), primarily due to the large amount of time spent in that location (an average of 72% - 77%). Although not a reference method for measuring mass concentration, the nephelometer did help identify PM sources and the relative contribution of those sources to an individual's personal exposure.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract #68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
JOURNAL Impact of Aerosol Liquid Water on Secondary Organic Aerosol Yields of Irradiated Toluene/Propylene/NOx/(Nh4)2SO4/Air Mixutres 08/01/2000
Edney, E. O., D. J. Driscoll, R. E. Speer, W. S. Weathers, T. E. Kleindienst, W. Li, AND D. F. Smith. Impact of Aerosol Liquid Water on Secondary Organic Aerosol Yields of Irradiated Toluene/Propylene/NOx/(Nh4)2SO4/Air Mixutres. ATMOSPHERIC ENVIRONMENT 34(23):3907-3919, (2000).
Abstract: Laboratory experiments were conducted to assess whether the presence of liquid water on pre-existing submicron ammonium sulfate aerosols affects yields of condensible organic compounds. Toluene/propylene/NOX/air mixtures were irradiated in the presence of submicron ammonium sulfate aerosol for a series of relative humidities and ammonium sulfate concentrations, generating aerosols containing organic and inorganic constituents with liquid water concentrations ranging from 4 to 66 ?g m-3. Organic aerosol carbon concentrations, measured on quartz filters, were corrected for uptake of gas phase organic compounds and converted into mass concentrations of the organic species. Concentrations of the aerosol ammonium, nitrate, sulfate, and liquid water, collected on co-located Teflon filters, were determined along with the total mass concentrations. Reasonable mass balances were found for the aerosols from summing the liquid water and the organic and inorganic components and comparing the totals to gravimetric determinations. A regression analysis showed the secondary organic aerosol yields, that were measured at near ambient concentration levels, could be expressed as a linear function of the organic mass concentration of the aerosol. The correlation coefficient of the regression did not improve by adding a term for aerosol liquid water concentrations in the regression. The results suggest that the presence of aerosol liquid water does not significantly increase or decrease SOA yields of the toluene oxidation products using quartz filters, although the possibility remains of some loss of water-soluble organic compounds by evaporation during handling of the filters.
The research described in this paper has been funded wholly by the US Environmental Protection Agency under Contract 68-D5-0049 to ManTech Environmental Technology, Inc. It has been subject to Agency review. Mention of trade names or commercial products does not constitute endorsement or recommended use.
JOURNAL The National Exposure Research Laboratory's Consolidated Human Activity Database 12/31/2000
McCurdy, T. R., G. Glenn, L. Smith, AND Y. Lakkadi. The National Exposure Research Laboratory's Consolidated Human Activity Database. INTERNATIONAL JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 10(6):566-578, (2000).
Abstract: EPA's National Exposure Research Laboratory (NERL) has combined data from 12 U.S. studies related to human activities into one comprehensive data system that can be accessed via the Internet. The data system is called the Consolidated Human Activity Database (CHAD), and it is available at http://www.epa.gov/nerl. CHAD contains 22,968 person-days of activity and is designed to assist exposure assessors and modelers in constructing population "cohorts" of people with specified characteristics that are suitable for subsequent analysis or modeling.
This paper describes the studies comprising CHAD and the various intellectual foundations that underlay the gathering of human activity pattern data. Next, it provides a brief overview of the Internet version of CHAD, and discusses how the program was formulated. Emphasis is placed on how activity-specific energy expenditure estimates were developed. Finally, the paper recommends steps that should be taken to improve the collection of activity data that would improve energy expenditure estimates and related information needed for physiologically-based exposure-dose modeling efforts.

The U.S. Environmental Protection Agency, through its Office of Research and Development, funded the development of the research described in this article under contract no. 68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
JOURNAL The 1998 Baltimore Particulate Matter Epidemiology-Exposure Study: Part 1 Comparison of Ambient, Residential Outdoor, Indoor and Apartment Particulate Matter Monitoring 12/31/2000
Williams, R. W., J. C. Suggs, R. B. Zweidinger, G. F. Evans, J. P. Creason, R. K. Kwok, C. E. Rodes, P. A. Lawless, AND L. S. Sheldon. The 1998 Baltimore Particulate Matter Epidemiology-Exposure Study: Part 1 Comparison of Ambient, Residential Outdoor, Indoor and Apartment Particulate Matter Monitoring. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 10(6):518-532, (2000).
Abstract: A combined epidemiological-exposure panel study was conducted during the summer of 1998 in Baltimore, Maryland. The objectives of the exposure analysis component of the 28-day study were to investigate the statistical relationships between particulate matter (PM) and related co-pollutants from numerous spatial boundaries associated with an elderly population, provide daily mass concentrations needed for the epidemiological assessment, and perform an extensive personal exposure assessment. Repeated 24-h integrated PM2.5 (n=394) and PM10 (n=170) data collections corresponding to stationary residential central indoor, individual apartment, residential outdoor and ambient monitoring were obtained using the same sampling methodology. An additional 325 PM2.5 personal air samples were collected from a pool of 21 elderly (65+ years of age) subjects. These subjects were residents of the 18-story retirement facility where residential monitoring was conducted. Mean daily central indoor and residential apartment concentrations were approximately 10 g/m3. Outdoor and ambient PM2.5 concentrations averaged 22 ug/m3 with a daily range of 6.7-59.3 ug/m3. The slope of the central indoor/outdoor PM2.5 mass relationship was 0.38. The average daily ratio of PM2.5/PM10 mass concentrations across the measurement sites ranged from 0.73 to 0.92. Both the central indoor and mean apartment PM2.5 mass concentrations were highly correlated with the outdoor variables (r>0.94). The lack of traditionally recognized indoor sources of PM present within the facility might have accounted for the high degree of correlation observed between the variables. Results associated with the personal monitoring effort are discussed in depth in Part 2 of this article.
The U.S. EPA, through its Office of Research and Development, funded and managed the research described here under contract no. 68-D5-0040 to the Research Triangle Institute. It has been subjected to agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
JOURNAL The 1998 Baltimore Particulate Matter Epidemiology-Exposure Study: Part 2-Personal Exposure Assessment Associated With An Elderly Study Population 12/31/2000
Williams, R. W., J. C. Suggs, J. P. Creason, C. E. Rodes, P. A. Lawless, R. K. Kwok, R. B. Zweidinger, AND L. S. Sheldon. The 1998 Baltimore Particulate Matter Epidemiology-Exposure Study: Part 2-Personal Exposure Assessment Associated With An Elderly Study Population. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 10(6):533-543, (2000).
Abstract: An integrated epidemiological-exposure panel study was conducted during the summer of 1998 which focused upon establishing relationships between potential human exposures to particulate matter (PM) and related co-pollutants with detectable health effects. The study design incorporated repeated individual 24-h integrated PM2.5 personal exposure monitoring. A total of 325 PM2.5 personal exposure samples were obtained during a 28-day study period using a subject pool of 21 elderly (65+ years of age) residents of an 18-story retirement facility near Baltimore, Maryland. Each sample represented a unique 24-h breathing zone measurement of PM2.5 mass concentration. PM2.5 and PM10 mass concentrations collected from the apartments of the subjects as well as residential and ambient sites were compared to individual and mean PM2.5 personal exposures. Daily PM2.5 personal exposure concentrations ranged from 2.4 to 47.8 ug/m3 with an overall individual study mean of 12.9 ug/m3. Mean PM2.5 personal exposures were determined to be highly correlated to those representing the central indoor (r=0.90) and ambient sites (r=0.89). Subjects reported spending an average of 92% of each day within the confines of the retirement center. Based upon measured and modeled exposures, a mean PM2.5 personal cloud of 3.1 ug/m3 was estimated. Data collected from these participants may be unique with respect to the general elderly population due to the communal lifestyle within the facility and reported low frequency of exposure to sources of PM.
The U.S. EPA, through its Office of Research and Development, funded and managed the research described here under contract no. 68-D5-0040 to the Research Triangle Institute. It has been subjected to agency review and approved for publication. Mention of trade names or commercial products does not constitute and endorsement or recommendation for use.
JOURNAL Comparison of PM 2.5 and PM 10 Monitors 12/31/2000
Williams, R. W., J. C. Suggs, C. E. Rodes, P. A. Lawless, R. B. Zweidinger, R. K. Kwok, J. P. Creason, AND L. S. Sheldon. Comparison of PM 2.5 and PM 10 Monitors. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 10(5):497-505, (2000).
Abstract: An extensive PM monitoring study was conducted during the 1998 Baltimore PM Epidemiology-Exposure Study of the Elderly. One goal was to investigate the mass concentration comparability between various monitoring instrumentation located across residential indoor, residential outdoor, and ambient sites. Filter-based (24-h integrated) samplers included Federal Reference Method Monitors (PM2.5-FRMs), Personal Environmental Monitors (PEMs), Versatile Air Pollution Samplers (VAPS), and cyclone-based instruments. Tapered element oscillating microbalances (TEOMs) collected real-time data. Measurements were collected on a near-daily basis over a 28-day period during July-August, 1998. The selected monitors had individual sampling completeness percentages ranging from 64% to 100%. Quantitation limits varied from 0.2 to 5.0 ug/m3. Results from matched days indicated that mean individual PM10 and PM2.5 mass concentrations differed by less than 3 ug/m3 across the instrumentation and within each respective size fraction. PM10 and PM2.5 mass concentration regression coefficients of determination between the monitors often exceeded 0.90 with coarse (PM10-2.5) comparisons revealing coefficients typically well below 0.40. Only one of the outdoor collocated PM2.5 monitors (PEM) provided mass concentration data that were statistically different from that produced by a protoype PM2.5 FRM sampler. The PEM had a positive mass concentration bias ranging up to 18% relative to the FRM prototype.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under EPA-NERL contract #68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.

JOURNAL The 1999 Fresno Particulate Matter Exposure Studies: Comparison of Community, Outdoor, and Residential PM Mass Measurements 11/01/2000
Evans, G. F., V. R. Highsmith, L. S. Sheldon, J. C. Suggs, R. W. Williams, R. B. Zweidinger, J. P. Creason, D. Walsh, C. E. Rodes, AND P. A. Lawless. The 1999 Fresno Particulate Matter Exposure Studies: Comparison of Community, Outdoor, and Residential PM Mass Measurements. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION 50(11):1887-1896, (2000).
Abstract: Two collaborative studies have been conducted by the USEPA National Exposure Research Laboratory (NERL) and the National Health and Environmental Effects Research Laboratory (NHEERL) to determine personal exposures and physiological responses to particulate matter (PM) for elderly persons living in a retirement facility in Fresno, California. Measurements of PM and other criteria air pollutants were made inside selected individual residences within the retirement facility and at a central outdoor site on the premises. In addition, personal PM exposure monitoring was conducted for a subset of the participants, and ambient PM monitoring data were available for comparison from the NERL PM Research Monitoring Platform in central Fresno. Both a winter (February 1-28, 1999) and a spring (April 19 - May 16, 1999) study were completed so that seasonal effects could be evaluated. During the spring study, a more robust personal exposure component was added, as well as a more detailed evaluation of physical factors, such as air exchange rate, which are known to influence the penetration of particles into the indoor environment. In this paper, comparisons are made among measured personal PM exposures and PM mass concentrations measured at the NERL Fresno Platform site, outside on the premises of the retirement facility, and inside selected residential apartments at the facility during the two 28-day study periods. The arithmetic daily mean personal PM2.5 exposure during the winter study period was 13.3 ug/m3, compared with 9.7, 20.5, and 21.7 ug/m3 for daily mean overall apartment, outdoor, and ambient (i.e., platform) concentrations, respectively. The daily mean personal PM2.5 exposure during the spring study period was 11.1 ug/m3, compared with 8.0, 10.1, and 8.6 ug/m3 for the daily mean apartment, outdoor, and ambient concentrations, respectively.
The information in this document has been funded wholly or in part by the U.S. Environmental Protection Agency through Contract No. 68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and publication. Mention of trade names or commercial products does not constitutute an endorsement or recommendation for use.
JOURNAL Measurement of Multi-Pollutant and Multi-Pathway Exposures in a Probability-Based Sample of Children: Practical Strategies for Effective Field Studies 12/31/2000
Adgate, J. L., C. A. Clayton, J. J. Quackenboss, K. W. Thomas, R. W. Whitmore, E. D. Pellizzari, P. J. Lioy, P. Shubat, C. Stroebel, N. G. Freeman, AND K. G. Sexton. Measurement of Multi-Pollutant and Multi-Pathway Exposures in a Probability-Based Sample of Children: Practical Strategies for Effective Field Studies. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 10(S6):650-661, (2000).
Abstract: The purpose of this manuscript is to describe the practical strategies developed for the implementation of the Minnesota Children's Pesticide Exposure Study (MNCPES), which is one of the first probability-based samples of multi-pathway and multi-pesticide exposures in children. The primary objective of MNCPES was to characterize children's exposure to selected pesticides through a combination of questionnaires, personal exposure measurements (i.e., air, duplicate diet, hand rinse), and complementary monitoring of biological samples (i.e., pesticide metabolites in urine), environmental samples (i.e., residential indoor/outdoor air, drinking water, dust on residential surfaces, soil), and children's activity patterns. A cross-sectional design employing a stratified random sample was used to identify homes with age-eligible children and screen residences to facilitate over sampling of households with higher potential exposures. Numerous techniques were employed in the study, including in-person contact by locally based interviewers, brief and highly focused home visits, graduated subject incentives, and training of parents and children to assist in sample collection. It is not feasible to quantify increases in rates of subject recruitment, retention, or compliance that resulted from the techniques employed in this study. Nevertheless, results indicate that the total package of implemented procedures was instrumental in obtaining a high percentage of valid samples for targeted households and environmental media.
Although the research described in this article has been funded, in part, by the EPA, it has not been subjected to review and therefore does not necessarily reflect the views of the agency, and no official endorsement should be inferred.
PRESENTATION Use of Fast Gc/Tofms as Reference Standard for Field Comparison Studies With on-Site Instruments 01/23/2000
Berkley, R. E., P. Ebersold, AND K. D. Oliver. Use of Fast Gc/Tofms as Reference Standard for Field Comparison Studies With on-Site Instruments. Presented at Eight International Conference, On-Site Analysis, Las Vegas, NV, January 23-26, 2000.
Abstract: A faster reference standard for field comparison studies of portable gas chromatographs (PGC) is needed. A performance evaluation of a high-speed GCMS (FGC/MS) system conducted during 1998 demonstrated generally satisfactory performance, but it was evident that performance of both the FGC/TOFMS and the PGC could be improved. Equipment and procedures have been further optimized, and the field study repeated. A performance evaluation conducted subsequent to the modifications is reported.
The information in this document has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Use of Continuous Nephelometer to Measure Personal Exposure to Particulate Matter During the 1998 U.S. EPA Baltimore Panel Study 01/25/2000
HowardReed, C., M. J. Zufall, J. M. Burke, R. W. Williams, J. C. Suggs, D. B. Walsh, R. K. Kwok, AND L. S. Sheldon. Use of Continuous Nephelometer to Measure Personal Exposure to Particulate Matter During the 1998 U.S. EPA Baltimore Panel Study. Presented at PM2000 AWMA Conference, Charleston, SC, January 25-28, 2000.
Abstract: Personal exposures to particulate matter (PM) have typically been measured using filter samplers worn by the participants in exposure studies. Personal filter samplers, however, are limited to providing average mass concentrations integrated over a 12- to 24-hour period due to low sample flow rates and environmental PM concentrations. To better understand the short-term variation in personal PM exposure, continuous (one-minute averaging time) nephelometers were worn by five participants as part of a four-week study completed at a retirement center in Baltimore, Maryland. The personal nephelometer (pDR-1000, MIE, Inc.) is a passive instrument that uses light-scattering to measure particle number in the size range of 0.1 um to 10 um. Based on gravimetric calibration to an SAE Fine test dust (mmd = 2 to 3 um, bulk density = 2.60 to 2.65 g/cm3, refractive index 1.54), the pDR-1000 reports mass concentration. In addition to wearing the pDR-1000, participants also wore Personal Exposure Monitors (PEMs) with a 2.5 um cut-point) (24-hour integrated filter samples) and recorded their daily activities in 15 minute intervals.
The time-series plots of personal nephelometer data showed each participant's PM exposure to consist of a series of peaks of relatively short duration. The highest measured one-minute mass concentration was 2.5 mg/m3, which was two orders of magnitude greater than the associated 24-hour time-weighted average. Activities corresponding to a significant instrument response included: outdoor activities, transportation, laundry, cleaning, cooking, moving between microenvironm.ents, and removing/putting on the instrument. In comparison with the 2.5 um PEM filter samples, the pDR-1000 generally measured higher 24-hour integrated mass concentrations (geometric mean = 1.5, 0g = 2.0, n = 34). Although not a reference method .for measuring mass concentration, the pDR-1000 did provide useful information regarding the identification of PM sources and their relative contribution to one's personal exposure.

This work has been funded wholly or in part by the United States Environmental Protection Agency under contract 68-D5-0040. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does trot constitute endorsement or recommendation for use.
PRESENTATION Power Analysis of Linear Relationships Between Personal Exposure and Indoor/Outdoor PM 2.5 Concentrations at Baltimore and Fresno 01/25/2000
Suggs, J. C., R. W. Williams, AND J. P. Creason. Power Analysis of Linear Relationships Between Personal Exposure and Indoor/Outdoor PM 2.5 Concentrations at Baltimore and Fresno. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The National Exposure Research Laboratory is currently in the process of conducting panel studies to investigate personal exposure to particulate matter(PM). One of the primary goals of PM exposure studies is to establish mathematical relationships between personal exposure and indoor/outdoor concentrations of particle matter in the 0 - 2.5 um size range (PM2.5). Linear regression relationships were fitted using data from studies conducted at sites in Baltimore MD, and Fresno CA. The coefficient of determination R2 was calculated from the log likelihood ratio of restricted and unrestricted maximum likelihood estimations using the SAS mixed models procedure and allowing for first order auto-correlation in the residuals. The power of a statistical test is the probability of seeing a statistically significant relationship when it exists and is inextricably tied to the the significance level (a or Type T Error), and the sample size which, in this case, is the number of days of sampling. By using R2 to estimate the effect size and applying power analysis, we were able to determine the required sample sizes to achieve statistically significant results for the a = .05 and .10 significance levels for tests of the nullhypothesis Ha: R2 >0 versus several alternative hypotheses between zero and 1.0. This paper examines the results with a retrospective look using power calculations (post hoc) to see how well we did and what adjustments should be made to sample sizes for future exposure studies. Power curves are plotted showing the interrelationship between R2, N, and the power for
the a=.05 and. 10 significance levels.

This paper has been reviewed in accordance with the U. S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Effects of Human Activity Patterns on Personal PM 2.5 Concentrations of Residents in a Retirement Facility 01/25/2000
Zufall, M. J., J. M. Burke, R. W. Williams, J. C. Suggs, R. K. Kwok, D. B. Walsh, J. P. Creason, AND L. S. Sheldon. Effects of Human Activity Patterns on Personal PM 2.5 Concentrations of Residents in a Retirement Facility. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: Measurements of ambient, outdoor, indoor, and personal particulate matter concentrations (PM) were made at a multi-story retirement facility near Baltimore, MD from July 26 to August 21, 1998. The overall aim of this study was to quantify the relationships between these different PM measurements and between the concentration measurements and health endpoints in an elderly population (persons > 65 years old). Study participants wore personal PM2.5 monitors, recorded their activities, and underwent daily physical monitoring.
One of the specific goals was to determine to what extent an individual's activities affect their PM exposures. Personal PM2.5 concentrations averaged 13 ug/m3, while concentrations in individual apartments and outdoors averaged 11 ug/M3 and 22 ug/m3, respectively. Study participants generally remained in their apartments or inside the facility, and were outside of the retirement home less than 10% of the time. Analysis of time-activity information and PM measurements showed that the highest average personal PM2.5 concentrations generally occurred for people who traveled by car or bus, cooked, or were outdoors for a significant period of time. Although correlations between PM2.5 concentrations and time spent in specific activities/locations were weak across the entire population, individual correlations existed for time spent in vehicles, time spent in commercial buildings, and total "active" time (time spent outside of the facility or being physically active). In addition, statistical analyses were undertaken to determine the mass contribution to PM exposure made by specific activities, including: going outside, traveling by car or bus, cooking, exercising, cleaning, eating in a restaurant or dining facility, going to various commercial locations, and opening apartment windows.

This work has been funded wholly or in part by the United States Environmental Protection Agency under contract 68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION The Effect of Relative Humidity on the Uptake of Aromatic Oxidation Products on Submicron Ammonium Sulfate Aerosol 01/25/2000
Kleindienst, T. E., W. Li, C. D. McIver, T. S. Conver, E. O. Edney, D. J. Driscoll, AND R. E. Speer. The Effect of Relative Humidity on the Uptake of Aromatic Oxidation Products on Submicron Ammonium Sulfate Aerosol. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: Epidemiological studies have suggested that fine particulate matter (<2.5 um) is correlated with daily mortality and morbidity in urban areas. At present, no plausible biological or chemical mechanism explains these correlations. Thus, a more complete understanding of the composition and properties of ambient aerosols is essential. Secondary organic aerosol (SOA), an important component of ambient aerosols, is formed when products of gas-phase reactions partition into the aerosol phase. Establishing the chemical and physical parameters controlling the formation of secondary organic aerosols is an important issue because this mechanism can account for as much as 80% of the mass concentration of the organic aerosol. Recent work in these laboratories and others has begun to provide a quantitative basis for establishing the yields of SOA from the oxidation products of aromatic hydrocarbons for dry aerosol. However, considerable uncertainty remains on the influence of liquid water on the uptake of organic oxidation products.
To address this issue a laboratory system has been developed to investigate the effects of relative humidity and liquid water content of the aerosol on SOA formation and composition under highly controlled conditions. The system is based on an 11.3 cubic meter, Teflon-lined smog chamber operated in a dynamic mode. A series of laboratory experiments were carried out where toluene/propylene/NOx/air mixtures were irradiated in the presence of submicron ammonium sulfate aerosol over a range of relative humidities and ammonium sulfate concentrations, generating aerosols containing organic and inorganic constituents with liquid water concentrations ranging from 4 to 60 ugm-3. Concentrations of the aerosol ammonium, nitrate, sulfate, and liquid water collected on Teflon filters were measured along with the total mass concentrations. In addition, organic aerosol carbon concentrations were determined from co-located quartz filters and corrected for uptake of gas phase organic compounds. The organic mass concentrations were determined by multiplying the organic carbon concentration by a factor of 2.0 to account for hydrogen, nitrogen, and oxygen. The SOA yields were determined for organic aerosol concentrations ranging from 11 to 25 ug m-3 at a precision of +15%. The laboratory results did not show a significant correlation between the secondary organic aerosol yield and the aerosol liquid water concentration. In general the yields were in good agreement with those predicted using the dry aerosol model developed by Odum and co-workers. The results suggest that the presence of aerosol liquid water does not significantly increase SOA yields of the toluene oxidation products, although the possibility remains of some loss of water-soluble organic compounds by evaporation during handling of the filters.

The U. S. Environmental Protection Agency through its Office of Research and Development funded and collaborated in the research described here (Contract 68-D5-0049 with ManTech Environmental Technology, Inc.) It has been subjected to Agency review and approved for publication.
PRESENTATION The Relationships Between Personal PM Exposures for Elderly Populations and Indoor and Outdoor Concentrations for Three Retirement Center Scenarios 01/25/2000
Rodes, C. E., P. A. Lawless, G. F. Evans, V. R. Highsmith, L. S. Sheldon, R. W. Williams, A. F. Vette, AND J. P. Creason. The Relationships Between Personal PM Exposures for Elderly Populations and Indoor and Outdoor Concentrations for Three Retirement Center Scenarios. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: Personal exposure, indoor and outdoor concentration, "physical factor", and questionnaire data were collected in three retirement center settings, supporting broader PM-health studies of elderly populations. The studies varied geographically and temporally, with populations studied in Baltimore (MD) in the summer of 1998, and Fresno (CA) in the winter and spring of 1999. The sequential nature of the studies and the relatively rapid review of the :mass concentration data after each segment provided the opportunity to modify the experimental designs, including the information collected from activity and baseline questionnaires and physical factor (e.g. HVAC system operation, door and window opening, air exchange rate, etc.) measurements.Important focuses of all three exposure study designs were: (1) development of relationships of personal exposures with outdoor and indoor microenvironmental concentrations, (2) providing information to understand the differences between measured personal PM exposures, and those estimated based on a simple timeweighted microenvironmental model, and (3) estimating the proportions of personal exposures attributed to aerosols of ambient origin.
This paper will highlight personal exposure data and inter-relationships for the three retirement center settings, and identify the most probable influencing factors. The current limited availability of questionnaire results, and chemical speciation data beyond mass concentration for these studies, preclude assessments estimating personal exposures from models, and apportionments of personal exposure collections attributable to ambient aerosols.
Preliminary data suggest that personal PM exposures for the elderly in retirement centers are only modestly (if at all) higher than outdoor concentrations, as compared to previous general population exposure studies. This was due in part to a smaller number of indoor PM sources (e.g. non-smoking environments, limited cooking), and modestly aggressive indoor PM removal by the HVAC systems. While the penetration of outdoor (ambient) particles through the building shell and through open doors and windows provided the majority of the personal exposure aerosol, personal-to-outdoor ratios varied widely, depending on the exposure scenario.

This work has been funded wholly or in part by the U.S. Environmental Protection Agency under contract 68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names ox commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Aerosol Concentrations During the 1999 Fresno Exposure Studies as Functions of Size, Season, and Meteorology 01/25/2000
Lawless, P. A., C. E. Rodes, G. F. Evans, L. S. Sheldon, AND J. P. Creason. Aerosol Concentrations During the 1999 Fresno Exposure Studies as Functions of Size, Season, and Meteorology. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The 1999 Fresno exposure studies took place in February (winter season) and April/May (spring season) for two periods of four weeks. During that time, nearly-continuous measurements of outdoor aerosol concentrations were made with a scanning mobility spectrometer (TSI SNIPS) and an optical particle counter (PMS LASX). These instruments provide particle size distribution information from about 0.01 to 3 um.
The size distributions from the two sampling periods possessed similarities, but also substantial differences. In the winter test period the majority of PM2.5, mass was attributed to submicron aerosol assumed to be primarily ammonium nitrate, with very little contribution from larger sizes. In the spring test period the submicron mass contribution was much smaller, and a substantial part of the PM2.5 mass came from the coarse particle mode.

The paper examines the size distributions in detail over the test period and compares the computed PM2.5 mass concentrations to those from a collocated FRM sampler. The seasonal and diurnal dependencies of other submicron fractions are also examined. These include PM 0.1, PM-0,3 and PM1, By use of air mass trajectory modeling and meteorological data, probable sources of the particulate matter fractions can be assigned.

The results of the study show that the SNIPS-LASX instrument combination is potentially a valuable tool for PM concentration measurements, particularly for identifying components of the PM2.5 aerosol.

This work has been funded wholly or in part by the U.S. Environmental Protection Agency under contract 68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Indoor/Outdoor Aerosol Concentration Ratios During the 1999 Fresno Particulate Matter Exposure Studies as a Function of Size, Season, and Time of Day 01/25/2000
Vette, A. F., A. W. Rea, P. A. Lawless, C. E. Rodes, G. F. Evans, V. R. Highsmith, J. P. Creason, AND L. S. Sheldon. Indoor/Outdoor Aerosol Concentration Ratios During the 1999 Fresno Particulate Matter Exposure Studies as a Function of Size, Season, and Time of Day. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The 1999 Fresno particulate matter exposure studies tools place in February (winter season) and April/May (spring season) for two periods of four weeks. During that time, near-continuous measurements of indoor and outdoor aerosol concentrations were made with a scanning mobility particle spectrometer (TSI SMPS) and an optical particle counter (PMS LASX). Combined, these instruments provide particle size distribution from about 0.01 to 3 um. This data can be used to identify near real-time perturbations, not only in aerosol concentration, but also aerosol size.
The indoor concentrations were measured in a vacant apartment used as an office and sampling site for the project. A switching manifold was used to alternately collect samples of five minute duration indoors and outdoors. During the winter season, the HVAC system was run continuously throughout the monitoring period. During the spring season, the HVAC system was run intermittently and was more representative of the community residences. Doors and windows were kept closed in both seasons.

Although the aerosol number concentration measurements from the SMPS and LASX require a knowledge of particle specific gravity to compute aerosol mass concentrations, the ratio of indoor to outdoor concentration as a function of particle size does not. The concentration ratio provides information about the effects of ambient concentration levels on indoor concentration, while the size-dependence of the ratio gives information about HVAC effects on the indoor concentration.

During the winter season, the HVAC system was run continuously and resulted in filtering the indoor air substantially, while in the spring season, the filtration effect was smaller. During one test period, the HVAC system was shut down for a period of about 16 hours, including the overnight period when the apartment was unoccupied. During that time, the indoor/outdoor ratio data provided information about the aerosol penetration into the building. Indoor/outdoor particle number density and ratios over the full size spectrum were used to evaluate different sources of particles in the indoor and outdoor environment. The results indicate that activities such as opening and closing doors and windows, even for brief periods of time, greatly affects aerosol penetration. In addition, seasonal differences were observed in particle size distribution with fine aerosols (PM2 5) dominating during winter and coarse aerosols dominating during spring.

This work has been funded wholly or in part by the U.S. Environmental Protection Agency under contract #68D50040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
PRESENTATION Lessons Learned from Four Exposure Panel Studies: the U.S. EPA's Particulate Matter Studies Involving Elderly Cohorts 01/25/2000
Sheldon, L. S., R. W. Williams, R. B. Zweidinger, G. F. Evans, V. R. Highsmith, J. C. Suggs, C. E. Rodes, AND J. P. Creason. Lessons Learned from Four Exposure Panel Studies: the U.S. EPA's Particulate Matter Studies Involving Elderly Cohorts. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The U.S. Environmental Protection Agency and its collaborators are conducting a series of human exposure panel studies on elderly (65+ years) subpopulations. The primary objectives of these studies are
-To determine personal and indoor exposures to particles and related species;
-To determine the relationship between exposure and indoor, outdoor, and ambient air concentrations;
-To determine the factors that influence these relationships.

Four studies of elderly residents in retirement facilities have been conducted in collaboration with the U.S. EPA's National Health and Environmental Effects Research Laboratory (NHEERL). Studies were performed in Baltimore in January 1997 and July 1998 and in Fresno, California in February and April 1999. Each of the studies included three to four weeks of intensive personal or stationary monitoring of PM-related air pollutants and the collection of questionnaire and time/activity diaries froze study participants. This paper reports on successes of recruiting and retaining elderly subjects for personal and residential monitoring. It also reports on the monitoring designs for each study, their strengths and weaknesses for meeting study objectives, and utility of various approaches studied in the studies.

This work has been funded wholly or in part by the U.S. Environmental Protection Agency under contract #68-D50040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
PRESENTATION The 1999 Fresno Particulate Matter Exposure Studies: Comparison of Community, Outdoor, and Residential PM Mass Measurements 01/25/2000
Evans, G. F., V. R. Highsmith, L. S. Sheldon, J. C. Suggs, R. W. Williams, R. B. Zweidinger, J. P. Creason, D. B. Walsh, C. E. Rodes, AND P. A. Lawless. The 1999 Fresno Particulate Matter Exposure Studies: Comparison of Community, Outdoor, and Residential PM Mass Measurements. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: Two collaborative studies have been conducted by the USEPA National Exposure Research Laboratory (NERL) and the National Health Effects and Ecological Research Laboratory (NHEERL) to determine personal exposures and physiological responses to particulate matter (PM) and gaseous pollutant concentrations for elderly persons living in a retirement facility in. Fresno, California. The NHEERL was responsible for soliciting study participants from the facility and conducting physiological tests of their respiratory, cardiac and immune function. These tests were conducted daily over a 28-day period. The NERL was responsible for collecting concurrent daily measures of PM mass, toxic components of PM, and criteria air pollutants (i.e.,03 and CO). These measurements were made inside selected individual residences within the retirement facility and at an outdoor central site on the premises.
Personal PM exposure monitoring was conducted for a subset ofthe participants. In addition, complementary PM monitoring was conducted at the NERL PM Research Monitoring Platform in central Fresno to provide comparisons with the indoor/outdoor data. Both a winter and a spring study were completed so that seasonal effects could be evaluated. The winter study (Phase 1) was conducted from February 1-28, 1999. The spring study (Phase 2) was conducted from April 19 May 16, 1999. During Phase 2, in addition to repeating the measurements made in Phase 1, a more robust personal exposure component was added as well as a more detailed evaluation of physical factors, such as air exchange rate, which are known to influence the penetration of particles into the indoor environment. This paper will compare PM mass concentration measurements made at the NERL Platform site in Fresno, outside on the premises of the retirement facility, and inside selected residential apartments at the facility during the two 28-day study periods.

This work has been funded wholly or in part by the U.S. Environmental Protection Agency under contract #68-D50040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
PRESENTATION Individual Particle Analysis of Indoor, Outdoor, and Personal Samples from the 1998 Baltimore Retirement Home Study 01/25/2000
Conner, T. L., G. A. Norris, M. S. Landis, AND R. W. Williams. Individual Particle Analysis of Indoor, Outdoor, and Personal Samples from the 1998 Baltimore Retirement Home Study. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 1999.
Abstract: Particle sampling was conducted outdoors, indoors, in apartment residences, and on individual residents (i.e., personal samples) at a retirement center in the Towson area of northern Baltimore County. Concurrent particle sampling was conducted at a central community site closer to downtown Baltimore. The major objective o# this work was to use computer-controlled scanning electron microscopy with individual-particle x-ray analysis (CCSEM) to measure the chemical and physical characteristics of particles collected on polycarbonate filters at the indoor, outdoor and community sampling locations. Apartment residence and personal samples collected on Teflon& fiber filters were examined manually. These data and observations will contribute to the understanding of the sources of particulate matter found in various micro-environments.
The PERSONAL SEM? (PSEM) manufactured by R. J. Lee Instruments, Ltd., Trafford, PA, was used to conduct the analyses. The PSEM is capable of computer-controlled analysis of particles with a physical diameter greater than approximately 0.5 Vim, or smaller for particles composed of elements with bright backscattered-electron images (e.g., Pb). Rules were developed to classify particles based on their size, shape (aspect ratio), elemental composition, number of x-ray counts, and/or image brightness level. While the process of generating userdefined rules can be very timeconsuming and is, by nature, subject to human judgement, this approach was used to take advantage of the wealth of information provided by particle images and the unique ability of the human eye to interpret them.

The CCSEM results were consistent with the trajectories of the air masses associated with the samples examined (e.g., increased NaCl with the marine transport regime). Differences in particle number concentrations for certain rule-based particle classes were observed among the community, outdoor and indoor samples. These differences indicate the presence of local outdoor particle sources, as well as particles originating from indoor sources or activities. Qualitative differences among the selected personal and apartment residence samples were also observed. The CCSEM results show that, for the particles characterized by CCSEM, community-based sampling may not yield samples which are representative of the particles found indoors.

This work has been funded wholly or in part by the United States Environmental Protection Agency under contract #68-D5-0040 to the Research Triangle Institute and. under contract #68-D5-0040 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved, for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Comparison of Filter-Based and Continuous Particulate Matter Methodologies from Residential and Ambient Monitoring 01/25/2000
Williams, R. W., J. C. Suggs, R. B. Zweidinger, G. F. Evans, J. P. Creason, R. K. Kwok, C. E. Rodes, P. A. Lawless, AND L. S. Sheldon. Comparison of Filter-Based and Continuous Particulate Matter Methodologies from Residential and Ambient Monitoring. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: An extensive PM monitoring study was conducted during the 1998 Baltimore PM Epidemiology-Exposure Study of the Elderly. An exposure goal of this study was. to investigate the mass concentration variability between various monitoring instrumentation located across residential indoor, residential outdoor, and ambient sites. Filter-based (24-h integrated) samplers included Federal Reference Method Monitors (FRM), Personal Environmental Monitors (PEMs), Versatile Air Pollution Samplers (VAPS), and cyclone-based instruments, with Tapered Element Oscillating Microbalances (TEOMs) and nephelometers collecting continuous data. Measurements were collected on a near-daily basis over the course of a 28-day period in July-August, 1998. The selected monitors had individual sampling completeness percentages ranging from 64-100%. Instrument method quantitation limits varied from 0.2 to 5.0 yg/m3. Data from matched days indicated that mean individual PMio and PM2.5 mass concentrations differed by less than 3 ug/m3 across the instrumentation and within each respective size fraction. Mass concentrations between collocated outdoor instruments typically varied by less than 20% of their mean values. PM10 and PM2.5 mass concentration Pearson correlation coefficients between the various instruments often exceeded 0.90 with coarse (PM10-2.5) comparisons revealing correlations typically well below 0.50. All of the cited outdoor PM2.5 samplers were observed to provide mass concentrations statistically equivalent to those measured using a prototype PM2.5 FRM sampler.
This work has been funded wholly or in part by the U.S. Environmental Protection Agency under contract #68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
PRESENTATION Supercritical Fluid Extraction of Semi-Volatile Organic Compounds from Particles 01/25/2000
Vallero, D. A., J. L. Farnsworth, AND J. J. Peirce. Supercritical Fluid Extraction of Semi-Volatile Organic Compounds from Particles. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: A nitrogen oxide flux chamber was modified to measure the flux of semi-volatile organic compounds (SVOCs). Part of the modification involved the development of methods to extract SVOCs from polyurethane foam (PUF), sand, and soil. Breakthroughs and extraction efficiencies were determined for PUF, and supercritical fluid extraction (SFE) conditions, including temperature, dynamic time and solvent modification, were optimized for porous media in the chamber. These conditions were applied to airborne particle matter to determine the effect of different particle size and composition on extraction efficiencies.
This work has been funded wholly by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION A Computer-Controlled System for Generating Uniform Surface Deposits to Study the Transport of Particulate Matter 01/25/2000
Antley, J. T., J. Giglio, AND S. L. Harper. A Computer-Controlled System for Generating Uniform Surface Deposits to Study the Transport of Particulate Matter. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: Improved methods for measuring and assessing microenvironmental exposure in individuals are needed. How human activities affect particulate matter in the personal cloud is poorly understood. A quality assurance tool to aid the study of particle transport mechanisms (e.g., re-entrainment, resuspension, transdermal transport, pica) would be beneficial, as particle-bound contaminants in housedust and tracked-in soil can represent significant exposure hazards for adults and children.
To meet this need, a laboratory system has been constructed that deposits spatially uniform layers of dry particles (e.g., dust) onto surfaces. Advantages include the ability to deagglomerate and deposit fine particulate (including PM2.5) as well as large particles (500 micrometers Dp). Variations in loading average approximately 20 percent for tests using discreet particle size ranges for total surface loadings between 0.3 g/m2 and 19 g/m2. Repeatability across identically prepared tests averages 10 percent ? 5 percent. "Worst-case" accuracy tests indicated a target surface loading could be generated within 20 percent ? 10 percent.

An aluminum chamber houses particle delivery equipment, a computer-controlled positioning system, and a 0.61 m by 0.61 in target surface area. Media used during evaluations have included several size ranges of glass beads (30 < Dp < 500 micrometers), and Arizona Test Dust (1< 80 micrometers). Presieved particle size ranges may be mixed to create custom polydisperse size distributions. Tagged materials have been developed to determine the fate and transport of individual size ranges in a polydisperse mix.

Past uses include studies of particle transfer during track-in of pesticide laden soils; surface sampler performance; food contamination; and a human exposure study of particle transfer from coated surfaces due to dermal contact as a function of surface loading, particle size and dermal condition.

This work has been funded by the United States Environmental Protection Agency under Contract 68-D5-0040 to the Research Triangle Institute. It has been subjected to the Agency's peer review and has been approved for publication.
PRESENTATION The US EPA's Supersites Program 01/25/2000
Scheffe, R. D., M. N. Jones, P. A. Solomon, AND M. Pitchford. The US EPA's Supersites Program. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The PM2.5 monitoring program is dominated by gravimetric measurements (over 1000 mass samplers nationwide) specific for mass, where the primary objective is comparisons with the PMZ 5 National Ambient Air Quality Standards (NAAQS). The other major component of the network is the speciation program, estimated to deploy as many as 300 samplers nationwide, and dominated largely by filter based technologies. The speciation program is designed to characterize the chemical composition of air sheds across the nation to support the development of State Implementation Plans (SIPS) and for ongoing air quality trends analyses. Modifications to both the mass and speciation components have been made in response to advice from the scientific community encouraging more frequent mass and speciation sampling to assist health effects and exposure research efforts. Regardless of the monitoring objective of concern, there is a general consensus and widespread support for advancing sampling and analysis methods that lead toward more resolved aerosol compositions in time, chemistry, phase, and size with attendant reduction in sampling artifacts. US EPA's Supersites Program was conceived in recognition of this need to foster testing and eventual application of advanced methods as a complement to the more routine technologies envisioned at this stage of program deployment.
Based on a series of meetings and workshops with a wide spectrum of health and atmospheric scientists, the Supersites Program has evolved to incorporate three principal objectives:

1) SIPs ....support development of State Implementation Plans (SIP's) through improved understanding of sourcereceptor relationships leading to improved design, implementation, and tracking of control strategy effectiveness in the overall PM program;

2) health effects and exposure development of monitoring data and samples to support
health and exposure studies to reduce uncertainty in National Ambient Air Quality Standards setting and to enable improved health risk assessments; and

3) methods testing .... comparison and evaluation of emerging sampling methods with routine techniques to enable a smooth transition to advanced methods.

This paper will provide an overview of EPA's Supersites Program and expand on the links among it and the other PM monitoring networks.

This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Methods Intercomparison of Samplers for EPA's National PM 2.5 Chemical Speciation Network 01/25/2000
Solomon, P. A., W. J. Mitchell, D. B. Gemmill, M. P. Tolocka, G. A. Norris, R. W. Wiener, J. P. Homolya, S. I. Eberly, J. Rice, R. W. Vanderpool, R. W. Murdoch, S. Natarajan, AND E. D. Hardison. Methods Intercomparison of Samplers for EPA's National PM 2.5 Chemical Speciation Network. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The objective of this sampler intercomparison field study is to determine the performance characteristics for the collection of the chemical components of PM2.5 by the chemical speciation monitors developed for the national PM2.5 network relative to each other, to the Federal Reference Method (FRM), and to other historically accepted monitors. The samplers were compared for PM2.5 mass, sulfate, nitrate, ammonium, OC, EC, and 10 elements. While the FRM is the standard for mass, there are no such standards for the chemical components of PM2.5 Thus, this intercomparison established equivalency among methods on a species by species basis. For volatile species (e.g., ammonium nitrate and semi-volatile organic compounds), the FRM provides only a lower limit on the expected mass loading for that species, as there is potential for loss of these species from the inert Teflon filters. For stable species, the FRM should provide an accurate estimate of the mass loading for those species. The historical samplers will provide an additional set of samples for comparison; however, they still can only be compared on an equivalent basis as none represent a reference method sampler.
To obtain a wide range of atmospheric chemical and meteorological conditions under limited time constraints, the study was conducted simultaneously in four locations over a two month period at Philadelphia, PA, Phoenix, AZ, Rubidoux, CA, and Research Triangle Park, NC. Statistical analysis of the data involved comparisons among the different samplers to examine differences in the determined chemical components due to sampler design characteristics. The results of this four-city sampler intercomparison study will be presented and differences found among the samplers ,performance will be discussed in light of sampler characteristics.

This work has been funded wholly or in part by the United States Environmental Protection Agency. Portions of the work were performed under Contract No. 68-D5-0040 by Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION East Versus West in the US: Chemical Characteristics of PM 2.5 During the Winter of 1998 01/25/2000
Solomon, P. A., W. J. Mitchell, D. B. Gemmill, M. P. Tolocka, J. C. Suggs, G. A. Norris, R. W. Wiener, J. P. Homolya, R. W. Vanderpool, AND S. Natarajan. East Versus West in the US: Chemical Characteristics of PM 2.5 During the Winter of 1998. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: PM2.5 samples were collected for up to 20 days during January and February of 1998 in four US cities. Samplers were collected for 24-hr sampling periods every other day at Philadelphia, PA, Phoenix, AZ, Rubidoux, CA, and Research Triangle Park, NC. These cities were chosen due to their potentially different chemical characteristics of the ambient aerosol. Chemical characterization included, sulfate, nitrate, and ammonium by ion chromatography, elements by XRF, OC/EC by TOR, and mass by gravimetric analysis. Appropriate filter media were used to allow for chemical analysis by the routine methods to be employed in the National PM2.5 Chemical Speciation Network. Results will be presented of the wintertime chemical characteristics of the four cities studied showing the differences among US regions.
This work has been funded wholly or in part by the United States Environmental Protection Agency. Portions of the work were performed under Contract No. 68-D5-0040 by Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Evaluation of Computer-Controlled Scanning Electron Microscopy Applied to An Ambient Urban Aerosol Sample 01/25/2000
Willis, R. D., Y. Mamane, AND T. L. Conner. Evaluation of Computer-Controlled Scanning Electron Microscopy Applied to An Ambient Urban Aerosol Sample. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: Recent interest in monitoring and speciation of particulate matter has led to increased application of scanning electron microscopy (SEM) coupled with energy-dispersive x-ray analysis (EDX) to individual particle analysis. SEM/EDX provides information on the size, shape, composition, heterogeneity, and possible sources of ambient particles. Such analyses are often costly and time-intensive. Computer-controlled scanning electron microscopy (CCSEM) allows automated analysis of particle size and elemental content of suitably prepared samples. Despite widespread use of CCSEM, data quality and accuracy are rarely discussed. In this paper we examine issues affecting the quality and validity of CCSEM data. Specifically, we assess the stability of unattended CCSEM over several hours, evaluate the sensitivity of CCSEM results to initial instrument settings, confirm the accuracy of particle volume and mass estimates by CCSEM, and determine the number of particles that must be analyzed in order to yield representative results.

CCSEM was applied to an urban aerosol sample collected on a polycarbonate filter with a dichotomous sampler. More than 2800 particles from 78 randomly selected fields were analyzed over an 8-hour period. Particle diameters and aspect ratios, X-ray counts of 20 elements, and images of each particle and its field of view were stored. Results show that a minimum of several hundred particles is needed to ensure representative results, while little additional information is gained by analyzing more than 1000 particles. The study demonstrated the stability of CCSEM over many hours. We conclude that CCSEM is a powerful tool for the characterization of individual atmospheric particles and a valuable complement to bulk analysis techniques.

This work has been funded wholly or in part by the United States Environmental Protection Agency under contract #68-D5-0049 to ManTech Environmental Technology, Inc. and under purchase order #9D-0710-NTTX for Dr. Yaacov Mamane. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION The Atlanta Supersite Project 01/25/2000
Solomon, P. A., W. L. Chameides, E. S. Edgerton, R. D. Scheffe, AND M. Pitchford. The Atlanta Supersite Project. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The Atlanta Supersites project is the first of two Supersites projects to be established during Phase I of EPA's Supersites Program; Phase 11 is being established through a Request for Assistance. The other initial project is in Fresno, California. The Supersites Program is part of EPA's National PM2.5 network, which consists of about 1100 sites four PM2.5 mass measured by the FRM and about 250-300 sites where the major components of PM2.5 will be determined. The objectives of the Supersites Program are to obtain information on atmospheric processes and provide information to assist states with State Implementation Plans (SIPS) for PM2.5, to support health effects related studies, and to evaluate measurement methods four particulate matter (PM) and PM precursors. The Atlanta Supersites project is focused on the last of these objectives, but meets the other objectives through leveraging with ongoing studies, including the Southeastern Aerosol Research Characterization Study (SEARCH), Aerosol Research Inhalation Epidemiological Study (ARIES), Southern Center For the Integrated Study of Secondary Air Pollutants (SCISSAP), and others. Specifically, evaluations at Atlanta focused on state-of-the-science measurement methods for PM and PM precursors and related species. Methods evaluated as part of the Atlanta Supersite project included four single particle mass spectrometer type methods, a series of semi-continuous methods for mass, sulfate, nitrate, ammonium, gas phase counter parts and other related species, and integrated filter/denuder based methods for PM2.5 mass and the chemical components of mass. Sampling occurred over a 28 day period during the month of August at a SEARCH/AREIS site located in NE Atlanta. This paper will describe the objectives and design of the Atlanta Supersite project and present preliminary results, where available.
This work has been funded wholly or in part by the United States Environmental Protection Agency through internal funding. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Use of PBPK/Pd Models and Foliar Transfer Coefficients in Assessing Reentry Into Pesticide Treated Citrus and Turf 03/19/2000
Knaak, J. B., C. C. Dary, G. T. Patterson, AND J. N. Blancato. Use of PBPK/Pd Models and Foliar Transfer Coefficients in Assessing Reentry Into Pesticide Treated Citrus and Turf. Presented at Annual Meeting of Society of Toxicology, Philadelphia, PA, March 19-23, 2000.
Abstract: Physiologically based pharmacokinetic and pharmacodynamic (PBpK/PD) models describing the fate of dermally applied "C-ring labeled ethyl parathion and isofenphos and inhibition of H-esterases (acetyleholin-, butyrylcholine-and carboxyl-) by oxons in the rat were used in conjunction with foliar transfer coeffcients to assess reentry levels/intervals into treated citrus (parathion) and turf (isofenphos) to harvest fruit ox for recreational use, respectively. Michaelis-Menten kinetics were used to describe the desulfuration of parathion and isofenphos to their oxons and hydrolysis of parent chemicals and oxons. Bimolecular rate constants, ki (pM'1 hr'1) were used to describe inhibition. Rates for enzyme synthesis, reactivation and aging were considered. A foliar transfer coefficient (slope of the regression line relating exposure in pg/h and foliar dislodgeable residue in ug/cm2, (twosided leaf residue) of 104 cm2/h was used in both models. According to the PBPK/PD models, -3% of the parathion and isofenphos foliar residues transferred to human skin were dermally absorbed over an 8 hr wok day in citrus or 2 hz on turf. Exposure to foliar residues of 0.09 ug/cm2 (two-sided leaf residue) of parathion on citrus and 0.6 p,g/cmz (two-sided leaf residue) of isofenphas on turf resulted in no red blood cell cholinesterase inhibition. On the basis of ChE NOELS of 0.05 mg/kg/day for parathion and isofenphos in chronic studies, margin of exposures (MOEs) of 16 and 10, respectively, were calculated.
The U.S. Environmental protection Agency (EPA), through its Office of Research and Development, participated in this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by the EPA.
PRESENTATION An Advanced PBPK Model Input System and Data Repository for Complex Models With Export for the Acsl Model Engine 03/19/2000
Power, F. W., J. N. Blancato, A. Ruiz, J. Licitra, J. J. Ventresca, AND R. N. Brown. An Advanced PBPK Model Input System and Data Repository for Complex Models With Export for the Acsl Model Engine. Presented at Annual Meeting of Society of Toxicology, Philadelphia, PA, March 19-23, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Application and Use of Dose Estimating Exposure Model (Deem) for Dose Comparisons After Exposure to Trichloroethylene (Tce) 03/19/2000
Blancato, J. N., F. W. Power, AND J. W. Fisher. Application and Use of Dose Estimating Exposure Model (Deem) for Dose Comparisons After Exposure to Trichloroethylene (Tce). Presented at Annual Meeting of Society of Toxicology, Philadelphia, PA, March 19-23, 2000.
Abstract: Route-to-route extrapolations are a crucial step in many risk assessments. Often the doses which result In toxicological end points in one route must be compared with doses resulting from typical environmental exposures by another route. In this case we used EPA's Dose Estimating Exposure Model (DEEM) to examine the route comparisons of different measures of internal dose after exposure to TCE. DEEM is a physiologically based model architecture for estimating internal tissue doses resulting from actual or simulated exposures. Because of different kinetic rates in the body not each possible measure of dose has the same quantitative relationship with exposure. Modeling shows that for different choices of internal dose the "equivalent" exposures are different, For example, we first chose the dose of interest to be the area under the curve (AUC) of the metabolite, trichloroacetic acid (TCA). In this case and with this model set-up an 8-hour 30 ppm exposure via inhalation was equivalent to drinking water intake of 50mg per day. For other measures of dose the point of equivalent exposure is far different. Thus, information about the mode of action and selection of internal dose is crucial before route to route extrapolations can be rationally made,
The U.S. Environmental Protection Agency (EPA). through Its Office of Research and Development, funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by the EPA.
PRESENTATION Uncertainty Analysis of Tce Using the Dose Exposure Estimating Model (Deem) in Acsl 03/19/2000
Tsang, A. M., R. N. Brown, F. W. Power, J. N. Blancato, AND C. S. Scott. Uncertainty Analysis of Tce Using the Dose Exposure Estimating Model (Deem) in Acsl. Presented at Annual Meeting of Society of Toxicology, Philadelphia, PA, March 19-23, 2000.
Abstract: The ACSL-based Dose Exposure Estimating Model(DEEM) under development by EPA is used to perform art uncertainty analysis of a physiologically based pharmacokinetic (PSPK) model of trichloroethylene (TCE). This model involves several circulating metabolites such as trichloroacetic acid (TCA) and trichloroethanol (TCOH) whose exact clearance parameter values are not always well known. A combined sensitivity and Monte Carlo analysis is presented. Some base model parameter values and associated experimental measurements were supplied by Fisher, et al. For imprecisely known parameters, sensitivity analyses use reasonable assumptions about parameter central tendency and natural variation. The natural variation is used in model runs to identify the most sensitive model parameters under various linear and nonlinear model concentration conditions. Using various sets of sensitive parameters, mixed normal and non-normal statistical distributional assumptions are used in Monte Carlo analyses under the assumption of independently varying parameters. Adjustments are made for correlated parameters. Central tendency and upper and lower percentile bounds are provided for time-dependent concentration curves of TCE, TCA, and TCOH, along with similar results for summary dose measures such as steady-state concentrations or area under the concentration curves. Experimental concentration measurements are plotted against predicted model variability.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has riot been peer reviewed by the EPA. Mention of trade names or commercial products does riot constitute endorsement or recommendation for use.
PRESENTATION Chemomorphic Analysis of Malathion in Skin Layers: Implications for the Use of Dermatopharmacokinetic (Dpk) Tape Stripping in Exposure Assessment to Pesticides 03/19/2000
Dary, C. C., Z. Mohammed, AND M. A. Saleh. Chemomorphic Analysis of Malathion in Skin Layers: Implications for the Use of Dermatopharmacokinetic (Dpk) Tape Stripping in Exposure Assessment to Pesticides. Presented at Annual Meeting of Society of Toxicology, Philadelphia, PA, March 19-23, 2000.
Abstract: The dermatopharmacokinetic (DPK) method of dermal tape stripping may prove to be a valuable addition to risk assessment protocols for toxic substances. To examine this possibility, the dermal penetration and absorption characteristics of [14C]-malathion inthe Sprague-Dawley rat was examined by three analytical techniques. [14C]-malathion was applied in different vehicles for 3U-minute and one-hour periods of exposure. Penetration into the stratum corneum (SC) was assessed by tape stripping followed by Instant Electronic Autoradiography (IEA). Also, the [14C]-activity retained in three successive 16pm sections of the skin application site was determined by IRA and malathion was identified by Fourier Transform Infrared Microscopy (FTIR microscopy)- Absorbed [14C]-malathion was measured in selected tissues, organs, and the residual carcass by Liquid Scintillation Counting (LSC). Penetration into the SC followed a linear trend. The capacity of the SC reservoir for malathion amounted to approximately 1?to of the dermal dose, while approximately 6% of the dose was absorbed. Results from this study support the view that LSC remains the method of choice to efficiently and reliably quantify absorption of a radiolabelled test substance. IEA offers the ability of the user to visualize the extent and profile of dermal absorption. When IEA is combined with FTIR microscopy, an effectual tool for studying the penetration of chemicals into layers of the skin emerges. The combined use of the three analytical techniques can be used to test the validity of the DPK method in hazard evaluation and exposure assessment of the organophosphorus insecticides.

The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development, participated in this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by the EPA.
PRESENTATION Predicting Population Exposures to PM: the Importance of Microenvironmental Concentrations and Human Activities 01/25/2000
Burke, J. M., M. J. Zufall, A. H. Ozkaynak, J. Xue, AND J. Zidek. Predicting Population Exposures to PM: the Importance of Microenvironmental Concentrations and Human Activities. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The Stochastic Human Exposure and Dose Simulation (SHEDS) models being developed by the US EPA/NERL use a probabilistic approach to predict population exposures to pollutants. The SHEDS model for particulate matter (SHEDS-PM) estimates the population distribution of PM exposure by sampling from distributions of ambient PM concentrations and from distributions of emission strengths for indoor sources of PM, such as cigarette smoking and cooking. A steady-state mass-balance equation is used to calculate PM concentrations for the home microenvironment. The physical factors data used in the equation (e.g., air exchange rate, penetration rate, deposition rate) are also sampled from distributions. Non-residential microenvironmental concentrations are calculated based on penetration of outdoor PM and indoor sources. Additional model inputs include demographic data for the population being modeled and human activity pattern data from the National Human Activity Pattern Survey (NHAPS). Output from the SHEDS-PM model includes distributions of PM exposures in various microenvironments (indoors at home, in vehicles, outdoors, etc.) and the relative contributions of these various microenvironments to the total exposure. SHEDS-PM has been applied to the population of Vancouver, Canada using spatially interpolated ambient PM measurements. The resulting distributions of PM exposures showed significant differences within population cohorts that was influenced by variability in human activities and in the contributions from indoor sources, such as smoking or cooking. The relative contributions of the different microenvironments to the total exposures indicate that the physical factors data used to calculate microenviromental concentrations need to be improved. Additional model developments underway include modifications to the input parameters required for modeling PM2.5 exposures, and application of SHEDS-PM to an urban. population in the United States.
This abstract has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Evaluation of Air Purification Devices for Control of Indoor PM 01/25/2000
Buckley, T. J. AND L. A. Wallace. Evaluation of Air Purification Devices for Control of Indoor PM. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: Because people spend most of their time indoors (89%), the indoor environment is a primary determinant of particle exposure. The indoor environment is especially an important determinant for the very young, the very old, and those with underlying cardiopulmonary disease because these population subgroups may spend an even larger fraction of their time indoors and they are susceptible to adverse effects from particle exposure. The concentration of PM indoors can be controlled by reducing their generation or increasing their removal. Commercial home air purifiers are a potential means for increasing removal. The purpose of this study was to evaluate the effectiveness of a 350 cfin HEPA air purifier for reducing indoor PM concentrations in an occupied residence. We conducted a single home (385 m3, 3-story townhouse) longitudinal study to investigate the effectiveness of a commercial home air purifier. Indoor particles were generated by typical activities including cooking, cleaning, and incense and candle burning, which were recorded on an indoor air time-activity diary. Particles ranging in size from 0.010 to 20 ,um were measured using a Scanning Mobility Particle Sizer (TS1, Inc, St.Paul, MN), an Aerodynamic Particle Sizer (TSI, St. Paul, MN)and a laser particle counter (Climet CI-500). The effectiveness of the home air cleaner was evaluated based on the depression in steady state particle concentration associated with the activation and deactivation of the room air purifier. Indoor air 12-h exchange rates were measured using a Bruel & Kjaer Model 1302 SF6 monitor (Bruel & Kjaer, Denmark). Results suggest that the effectiveness of the purifier is particle size dependent, yielding a decrease in a 3m X 4m room ranging from 10% to 40% for ultrahne particles and 80% for particles from 0.5 to 10 ,um. These results suggest that HEPA air purifiers with high air flow rates are effective in reducing indoor PM and that such devices may provide an effective tool for protecting susceptible populations such as asthmatics or persons with chronic obstructive pulmonary disease.
This work has been funded in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recormnendation for use.
PRESENTATION Assessment of Outdoor, Indoor, and Personal PM Concentration Differences By Continuous Monitoring 01/25/2000
LaRosa, L., T. J. Buckley, C. HowardReed, AND L. A. Wallace. Assessment of Outdoor, Indoor, and Personal PM Concentration Differences By Continuous Monitoring. Presented at Air and Waste Management Association Meeting, Charleston, SC, January 25-28, 2000.
Abstract: Many sources and factors affect the particle concentrations inside a home, often causing indoor PM concentrations to be higher than outdoors. Furthermore, daytime personal PM exposures are, on average, 50% higher than that indicated by stationary monitoring. The increased concentration around the individual has been termed the "personal cloud". The purposes of this study were to compare the personal, indoor and outdoor PM concentrations, to further characterize the "personal cloud", and to examine the contribution of pets (two large, active dogs) and other indoor sources to indoor PM concentrations. Four MZE Data RAM personal monitors (MIE, Bedford, MA) and two to four Climets -5001 (Climet Instruments, Redlands, CA) were used to measure real-time indoor and outdoor PM concentrations at a Maryland residence for two months. To study the personal cloud, an MIE monitor was worn during indoor activities such as office work and exercising on a rowing machine. These activities allowed the comparison of PM levels during passive versus active indoor activities. Because the Climets and MIEs were operated side-by-side during data collection, the results generated by the two instruments were compared for PMIp concentrations. Preliminary results indicate that elevated indoor particle levels (2.5 to X10 pm) were detected indoors when there was human and pet activity in a room. Furthermore, levels of particles ranging in size from 5 to >l0~tm were significantly higher indoors than outdoors when there was activity inside the home. However, fine PM concentrations (0.3 to 1.0 gym) were usually higher outside, except during cooking or candle burning activities. Petting dogs and patting clothes increased the magnitude of the personal cloud. This characterization of indoor and personal PM addresses uncertainties in PM exposure and will be useful for modeling indoor particle concentrations and designing intervention strategies.

This work has been funded in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Monitoring Particles, Soot, and PAHs in a Home 01/25/2000
Wallace, L. A., C. HowardReed, L. LaRosa, AND S. J. Emmerich. Monitoring Particles, Soot, and PAHs in a Home. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The Atlanta Supersites project is the first of two Supersites projects to be established during Phase I of EPA's Supersites Program; Phase II is being established through a Request for Assistance. The other initial project is in Fresno, California. The Supersites Program is part of EPA's National PM2.5 network, which consists of about 1100 sites for PM2.5 mass measured by the FRM and about 250-300 sites where the major components of PM2.5 will be determined. The objectives of the Supersites Program are to obtain information on atmospheric processes and provide information to assist states with State Implementation Plans (SIPS) for PM2.5, to support health effects related studies, and to evaluate measurement methods for particulate matter (PM) and PM precursors. The Atlanta Supersites project is focused on the last of these objectives, but meets the other objectives through leveraging with ongoing studies, including the Southeastern Aerosol Research Characterization Study (SEARCH), Aerosol Research Inhalation Epidemiological Study (ARIES), Southern Center For the Integrated Study of Secondary Air Pollutants (SCISSAP), and others. Specifically, evaluations at Atlanta focused on state-of the science measurement methods for PM and PM precursors and related species. Methods evaluated as part of the Atlanta Supersite project included four single particle mass spectrometer type methods, a series of semicontinuous methods for mass, sulfate, nitrate, ammonium, gas phase counter parts and other related species, and integrated filter/denuder based methods for PM2.5 mass and the chemical components of mass. Sampling occurred over a 28 day period during the month of August at a SEARCH/AREIS site located in NE Atlanta. This paper will describe the objectives and design of the Atlanta Supersite project and present preliminary results, where available.
This work has been funded wholly or in part by the United States Environmental Protection Agency through internal funding. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Predicting Particulate (PM-10) Frequency Distributions for Urban Populations Using a Random Component Superposition Model (Rcs) Model 01/25/2000
Ott, W. R., L. A. Wallace, AND D. T. Mage. Predicting Particulate (PM-10) Frequency Distributions for Urban Populations Using a Random Component Superposition Model (Rcs) Model. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: Health risk evaluations usually require the frequency distribution of personal exposures of a given population. For particles, personal exposure field studies have been conducted in only a few urban areas, such as Riverside, CA; Philipsburg, NJ; and Toronto, Ontario. This paper explores the concept that these exposure data, however limited, may allow prediction of distributions for other urban areas where personal exposure field studies have not yet been: carried out. To test this concept, a statistical model was developed that treats the indoor and outdoor components of concentration as independent random variables that are added together by the principle of superposition, or a random component superposition (RCS) model. The ambient concentrations entering indoors from outdoors are modified by a dimensionless attenuation coefficient. This model is consistent with our physical understanding of the factors affecting indoor particle concentrations and personal exposures, and it allows the incremental exposure distributions from different cities to be compared. The RCS model assumes that personal exposure is the sum of two independent random variables, one caused by personal activities and one caused by outdoor concentrations infiltrating indoors. The model predicts that the correlation coefficient r between the personal exposures and ambient concentrations will follow a specific nonlinear equation when the personal exposures of n persons are averaged together on a given date. The experimental data show reasonably good agreement with the predictions of this model. Since this model flows from our physical understanding of the process and the properties of the empirical data, it may be a suitable tool for predicting population exposure frequency distributions in other urban areas where exposure field studies have not yet been conducted.
This work has been funded in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Personal Exposures to PM and Gaseous Air Pollutants at the End of 1991 Kuwait Oil Fires 01/25/2000
AlRaheem, M., M. ElDesouky, D. T. Mage, M. Kollander, L. A. Wallace, AND J. D. Spengler. Personal Exposures to PM and Gaseous Air Pollutants at the End of 1991 Kuwait Oil Fires. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION US EPA's Supersites Program 03/01/2000
Solomon, P. A., R. D. Scheffe, AND M. Pitchford. US EPA's Supersites Program. Presented at Real World 2000, Clean Air Conference, Atlanta, GA, May 15-18, 2000.
Abstract: Dermal exposure to volatile organic compounds (VOCs) in water results from environmental contamination of surface, ground-, and drinking waters. This exposure occurs both in occupational and residential settings. Compartmental models incorporating body burden measurements have been developed to estimate VOC exposure through pathways of inhalation and ingestion. This modeling approach is needed for the dermal pathway as well because VOC dermal exposure in water can be significant. We present preliminary results of alveolar breath measurements as a biomarker for VOC dermal exposure. Models were developed from VOC dermal uptake and breath concentration measurements collected in a laboratory-based human in vivo study. Subjects placed their hand and forearm into a sealed 2-liter plexiglass cylinder containing 100, 100, 100, and 400 g/L of chloroform, toluene, 1,1,1-trichloroethane (111TCA) and methyl t-butyl ether (MTBE) in water, respectively, for one hour. The amount of dermal uptake was determined by measuring the change in water concentration from the beginning to the end of the exposure period. Concentrations of target VOCs in breath were measured before, during and after exposure in order to establish the concentration time-course associated with dermal uptake. Breath samples were collected via a single-breath exhalation procedure into Summa canisters. Breath sample analysis was conducted using a gas chromatography/mass spectrometry detector (GC/MS). This study develops mathematical, compartmental models to estimate VOC dermal exposure with body burden as a biomarker. This modeling approach is an effective and practical tool for held researchers to more fully characterize the population exposure distribution.
This study has been supported in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION Breath Measurement and Models to Assess VOC Dermal Absorption in Water 05/19/2000
Fan, V. S., T. J. Buckley, M. Colon, AND J. D. Pleil. Breath Measurement and Models to Assess VOC Dermal Absorption in Water. Presented at American Industrial Hygiene Conference and Exposition, 2000, Orlando, FL, May 19-25, 2000.
Abstract: Dermal exposure to volatile organic compounds (VOCs) in water results from environmental contamination of surface, ground-, and drinking waters. This exposure occurs both in occupational and residential settings. Compartmental models incorporating body burden measurements have been developed to estimate VOC exposure through pathways of inhalation and ingestion. This modeling approach is needed for the dermal pathway as well because VOC dermal exposure in water can be significant. We present preliminary results of alveolar breath measurements as a biomarker for VOC dermal exposure. Models were developed from VOC dermal uptake and breath concentration measurements collected in a laboratory-based human in vivo study. Subjects placed their hand and forearm into a sealed 2-liter plexiglass cylinder containing 100, 100, 100, and 400 g/L of chloroform, toluene, 1,1,1-trichloroethane (111TCA) and methyl t-butyl ether (MTBE) in water, respectively, for one hour. The amount of dermal uptake was determined by measuring the change in water concentration from the beginning to the end of the exposure period. Concentrations of target VOCs in breath were measured before, during and after exposure in order to establish the concentration time-course associated with dermal uptake. Breath samples were collected via a single-breath exhalation procedure into Summa canisters. Breath sample analysis was conducted using a gas chromatography/mass spectrometry detector (GC/MS). This study develops mathematical, compartmental models to estimate VOC dermal exposure with body burden as a biomarker. This modeling approach is an effective and practical tool for held researchers to more fully characterize the population exposure distribution.
This study has been supported in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION Evaluation of Analytical Methods for Determining Pesticides in Baby Food and Adult Duplicate-Diet Samples 03/26/2000
Chuang, J. C., K. Hart, J. S. Chang, A. W. Reed, AND J. M. Van Emon. Evaluation of Analytical Methods for Determining Pesticides in Baby Food and Adult Duplicate-Diet Samples. Presented at Immunochemistry Summit VIII Meeting, San Francisco, CA, March 26-31, 2000.
Abstract: Determinations of pesticides in food are often complicated by the presence of fats and require multiple cleanup steps before analysis. Cost-effective analytical methods are needed for conducting large-scale exposure studies. We examined two extraction methods, supercritical fluid extraction (SFE) and accelerated solvent extraction (ASE), coupled with various cleanup techniques for the analysis of pesticides in baby foods. The SFE-GC/MS method did not provide quantitative recoveries (<50%) of the pesticides spiked into fatty baby foods. This led to the evaluation of ASE-ELISA and ASE-GC/MS using a Dionex Model ACE 2000 system. Two solvents (acetonotrile [ACN] and ethyl acetate), three extraction temperatures (80?C, 100?C, and 120?C), and several different sample clean-up procedures were evaluated. A set of ASE conditions was developed that consists of extracting baby food with ACN at 80?C under 2,000 psi pressure. An ENVICarb SPE condition was also developed to clean the ACN extract. The cleanup fraction was analyzed by ELISA for chlorpyrifos and by GC/MS for malathion, chlorpyrifos, p,p'DDE, and p,p'-DDT. Duplicate diet samples were analyzed for target pesticides by ASELISA axed by ASE-GC/MS. Concentrations of these compounds ranged from <0.3 to 110 ppb.
This work has been funded wholly or in part by the U.S.EPA under contract 68D4-0023 to Battelle. It has been subjected to Agency review anal approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Determination of 3,5,6-Trichloro-2-Pyridinol (Tcp) By ELISA 03/26/2000
Van Emon, J. M., A. W. Reed, J. C. Chuang, A. Montoya, AND J. J. Manclus. Determination of 3,5,6-Trichloro-2-Pyridinol (Tcp) By ELISA. Presented at Immunochemistry Summit VIII Meeting, San Francisco, CA, March 26-31, 2000.
Abstract: A sensitive, competitive enzyme-linked immunosorbent assay (ELISA) for 3,5,6-trichloro-2pyridinol (TCP) has been developed to quantitate parts per billion (ppb) amounts of the analyte in urine. TCP is a major metabolite and environmental degradation product of the insecticide chlorpyrifos and the herbicide triclopyr. Thus, TCP can be used as a biomarker for monitoring levels of exposure or contamination from these pesticides. The least detectable dose estimated for this assay is 0.01 ppb in hydrolyzed and diluted urine samples. Immunoassay results have been compared with GC/MS measurements from occupational and nonoccupational exposure studies yielding good correlations (r=0.990 and r=0.970).
The U.S. Environmental Protection Agency (EPA) through its Office of Research and Development (ORD) funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Field Evaluation of Samplers for EPA's National PM 2.5 Chemical Speciation Network-Preliminary Results from Atlanta 05/01/2000
Solomon, P. A., W. J. Mitchell, D. B. Gemmill, M. P. Tolocka, G. A. Norris, AND R. W. Wiener. Field Evaluation of Samplers for EPA's National PM 2.5 Chemical Speciation Network-Preliminary Results from Atlanta. Presented at Real World 2000, Clean Air Conference, Atlanta, GA, May 15-18, 2000.
Abstract: The US EPA bas established a national network at nearly 1100 sites to monitor PM2.5 mass for testing compliance with the PM2.5 National Ambient Air Quality Standards. The objective of the field evaluation is to determine the performance characteristics for the collection of the chemical components of PM2.5 by the chemical speciation monitors developed for the national PM2.5 network relative to each other, to the Federal Reference Method (FRM), and to other historically accepted monitors. The samplers were initially compared in 4 cities throughout the US during January and February of 1999. The evaluations in Atlanta during August of 1999 represent a summertime test of these samplers. The samplers were compared for PM, mass, sulfate, nitrate, ammonium, OC, EC, and 10 elements. While the FRM is the standard for mass, there are no such standards for the chemical components of PM2.5, Thus, these intercomparison studies established equivalency among methods on a species by species basis. For volatile species (e.g., ammonium nitrate and semi-volatile organic compounds), the FRM provides only a lower limit on the expected mass loading for that species, as there is potential for loss of these species from the inert Teflon filters. For stable species, the FRM should provide an accurate estimate of the mass loading for those species. The historical samplers will provide an additional set of samples for comparison; however, they still can only be compared on an equivalent basis as none represent a reference method sampler.
Statistical analysis of the data involved comparisons among the different samplers to examine differences in the determined chemical components due to sampler design characteristics. The preliminary results of the Atlanta study will be presented and differences found among the samplers performance will be discussed in light of sampler characteristics. Results will also be compared to the 4 City Study intercomparison.

This work has been funded wholly or in part by the United States Environmental Protection Agency. Portions of the work were performed under Contract No. 68-D5-0040 by Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Analysis of the Flux of An Endocrine Disrupting Dicarboximide and Its Degradation Products from the Soil to the Lower Troposphere 03/26/2000
Vallero, D. A., L. Stockburger, J. L. Farnsworth, AND J. J. Peirce. Analysis of the Flux of An Endocrine Disrupting Dicarboximide and Its Degradation Products from the Soil to the Lower Troposphere. Presented at 219th American Chemical Society National Meeting, San Francisco, CA, March 26-31, 2000.
Abstract: A method for measuring the atmospheric flux of the antiandrogenic dicarboxirnide, vinclozolin, and its degradation products was investigated. A nitric oxide laboratory chamber was modified to measure the flux of semi-volatile compounds. Pesticide application systems and soil incorporation systems were designed and added to the chamber. The dicarboximides were collected using polyurethane foam plugs. A protocol was developed for chemical extraction, separation, and detection of dicarboximides. Concentration gradients were determined for semi-volatile organic compounds in a pesticide spray in the chamber. Experimental results demonstrated that polyurethane foam is an efficient trapping medium for dicaxboximides. Sample flow rate was found to be a major factor in the amount of dicarboximide mass breaking through the foam. Supercritical fluid extraction (SFE) was demonstrated to effectively remove the compounds from foam for chemical separation and detection. The SFE factors were optimized for recovering dicarboximides from porous media in the chamber. The factors varied by compound and type of porous media, but methanol modification appears to improve extraction efficiencies of soilbound dicarboximides. The research is presently addressing the extraction efficiencies of dicarboximides by SFE for fine and course ambient aerosols and comparing these efficiencies to those obtained using conventional extraction methods.
This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Comparison of Selected Lower Explosive Limit Meters Used By Usaf and Commercial Jet Fuel Tank Entry Personnel 05/19/2000
Jensen, P. A., S. Martin, M. J. Sapko, K. L. Cashdollar, K. E. Mura, L. Smith, D. Fritts, B. A. Blazicko, J. M. Reichert, AND J. D. Pleil. Comparison of Selected Lower Explosive Limit Meters Used By Usaf and Commercial Jet Fuel Tank Entry Personnel. Presented at American Industrial Hygiene Conference and Exposition, Orlando, FL, May 19-25, 2000.
Abstract: Thousands of military personnel and tens of thousands of civilian workers perform tank entry procedures. OSHA regulations (1910.146) require the internal atmosphere be tested, with a calibrated direct-reading instrument, for oxygen content, flammable gases and vapors, and potential toxic air contaminants before an employee enters the space. The USAF and NIOSH had previously identified the highest worker exposures during removal of fire suppressant foam from the fuel tanks of Hercules C-130 aircraft. In addition, the study noted that jet fuel vapor composition changed with time and ventilation.
In this study, lower explosive limit (LEL) meters were challenged with jet fuel vapor from fuel tanks of a Hercules C-130H and several commercially-available LEL span gases. The meters evaluated were based on three detection technologies: (1) infrared; (2) photoionization; (3) catalytic bead.

All meters were calibrated in accordance with manufacturer's specifications and with manufacturer-supplied calibration gas. All meters were used as provided by the manufacturers except 0.25-inch (ID) Teflon-lined tygon tubing was used in lieu of manufacturersupplied tubing. A Foxboro TVA 1000B, with flame-ionization detector, was used to measure total hydrocarbon content of the jet fuel vapor.

Overall, the FID was most sensitive, the photoionization detectors and infrared detector were second. The catalytic beads appeared bifurcated - Some were responsive and some were not to vapor compositions after ventilation. The traditional catalytic bead technology does not allow for the detection of n-alkanes (>C9); thus, after ventilation of the more-volatile fraction of jet fuel, a potentially-explosive or unsafe environment might go undetected. Overall, some LEL meters may significantly underestimate the explosive potential of jet fuel vapors in tanks after the light-end of jet fuel has been removed. A second major finding of this study is that manufacturer-recommended calibration techniques do not appear to match instrument performance to jet fuel vapor.
PRESENTATION Detection of Dna Damage Using a Fiberoptic Biosensor 03/26/2000
Rogers, K. R., A. B. Apostol, S. J. Madsen, AND C. W. Spencer. Detection of Dna Damage Using a Fiberoptic Biosensor. Presented at ACS National Meeting, San Francisco, CA, March 26-30, 2000.
Abstract: A rapid and sensitive fiber optic biosensor assay for radiation-induced DNA damage is reported. For this assay, a biotin-labeled capture oligonucleotide (38 mer) was immobilized to an avidin-coated quartz fiber. Hybridization of a dye-labeled complementary sequence was observed using the evanescent wave and reported at the proximal end of the optical fiber. Changes ire temperature-induced strand separation were then used as a sensitive indicator of damage resulting from exposure of the dye-labeled strand to low doses of ionizing radiation. Ten assays (each requiring about 15 main) could be run. on the same fiber. Radiation exposures of between 0.2 and 10 Gray (Gy) were measured.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by EPA.
PRESENTATION Immunoassays for Food Analysis 03/26/2000
Cullen, S. J., J. M. Van Emon, K. Robbins, AND A. W. Reed. Immunoassays for Food Analysis. Presented at Immunochemistry Summit VIII Meeting, San Francisco, CA, March 26-31, 2000.
Abstract: Chlorpyzifos is widely used in agriculture on fruits and vegetables. According to federal guidelines, tolerances for chlorpyrifos an produce range from 0.1 ppm to 8 ppm. Detection of these residues is commonly performed by gas chromatography; however, the cleanup required makes the procedure laborious and time-consuming. We have developed a streamlined approach for the detection of chlorpyrifos in various food matrices. The method utilizes a sonic extraction, followed by dilution and detection with either a magnetic particle enzyme linked irnmunosorbent assay (ELISA) or a plate ELISA. Recoveries ranged from 74-.95% for various baby foods (e.g., chicken noodle dinner, spinach, apple-banana, arid broccoli carrots arid cheese), Cleanup with solid phase extraction was not necessary but could be used for more difficult matrices. The ELISAs could tolerate 2% acetonitrile and up to 5% methanol. The plate ELISA has a detection range of 0.2 - 100 ppb while the magnetic particle assay has a limited range of 1-3 ppb. Chlorpyrifos levels of 5 - 400 ppb could be determined using a 10 g sample. The method is being extended to duplicate diet exposure samples.
The U.S.EPA through its Office of Research and Development (ORD) funded this research and approved this abstract as a basis for a poster presentation. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Comparison of Sampling Methods for Semi-Volatile Organic Carbon (Svoc) Associated With PM 2.5 01/25/2000
Lewtas, J., D. Booth, S. Reimer, Y. Pang, D. J. Eatough, AND L. A. Gundel. Comparison of Sampling Methods for Semi-Volatile Organic Carbon (Svoc) Associated With PM 2.5. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 1999.
Abstract: This study evaluates the influence of denuder sampling methods and filter collection media on the measurement of semi-volatile organic carbon (SVOC) associated with PM2.5. Two types of collection media, charcoal (activated carbon) and XAD, were used both in diffusion denuders and impregnated back-up filters in two different samplers, the VAPS and the PC-BOSS. The two organic diffusion denuders were XAD-coated glass annular denuders and charcoal-impregnated cellulose fiber filter (CIF) denuders. In addition, recently developed XAD-impregnated quartz filters were compared to CIF filters as back-up filter collection media. The two denuder types resulted in equivalent measurement of particulate organic carbon and particle mass. The major difference observed between the XAD and charcoal BOSS denuders is the higher efficiency of charcoal for collection of more volatile carbon. This more volatile carbon does not contribute substantially to the particle mass or SVOC measured as OC on quartz filters downstream of the denuders. This volatile carbon does result in high OC concentrations observed in charcoal filters placed behind quartz filters downstream of the XAD denuders and would result in overestimating the SVOC in that configuration.
This paper has been reviewed in accordance with the US Environmenal Protection Agency's peer and administrative review policies and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Overview of EPA Human Exposure Measurements Projects as Applied to Jp-8 Jet Fuel 01/10/2000
Pleil, J. D. AND L. Smith. Overview of EPA Human Exposure Measurements Projects as Applied to Jp-8 Jet Fuel. Presented at Toxicology of JP-8 Jet Fuel Conference, Tucson, AZ, January 10-12, 2000.
Abstract: One of the many responsibilities of the National Exposure Research Laboratory (NERL) of the U.S. Environmental Protection Agency (EPA) is the development and demonstration of methodology for assessing human exposure to environmental pollutants. As such, personnel from the Human Exposure and Atmospheric Sciences &vision (HEASD)of NERL/ EPA have been collaborating with the U.S. Air Force Surgeon General's staff in a series of laboratory and field activities to develop real-world data for an eventual risk assessment of military activity involving the chemical exposure to JP-8 jet fuel and its combustion byproducts. The primary focus has been the measurement of ambient vapor inhalation exposure and dermal contact exposure of fuel systems maintenance personnel through the use of whole-air sampling and exhaled breath analysis. Similar measurements focusing on vapors from engine exhaust exposure to ground crew personnel during pre-flight engine run-ups have also been performed. An article describing the results from a series of field studies has been accepted for publication (Environmental Health Perspectives, Feb. 2000). An ancillary project has been initiated to address the potential health concerns from particle bound poly-aromatic hydrocarbons (PAH) from aircraft exhaust; we are developing the capability for real-time measurement of total PAH to allow intelligent decision making for the use of respiratory protection equipment. An article concerning this project has been written and is currently under review. Finally, we are developing specific methodology for the exposure and dose assessment of JP-8 jet fuel constituents as found in human blood. We have published one article concerning methods development for blood in the Journal of Chromatography B, March 1999, and have a second article under review at Analytical Toxicology. The ambient, breath, and blood measurement methods will be part of the upcoming US Air Force epidemiological study on JP-8 jet fuel exposure.
This is an abstract of a proposed presentation and has been subjected to EPA review and approved for publication.
PRESENTATION Assessment of Indoor, Outdoor, and Personal PM Differences 01/25/2000
LaRosa, L., T. J. Buckley, C. HowardReed, AND L. A. Wallace. Assessment of Indoor, Outdoor, and Personal PM Differences. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 1999.
Abstract: Epidemiological studies have consistently demonstrated that a correlation exists between daily ambient particle concentrations and health effects.' One major area of concern with respect to particulate matter (PM) is the relationship between indoor and outdoor particle concentrations- Indoor particle concentrations are greatly affected by human activities, often resulting in poor correlations between indoor and outdoor PM concentrations. Z Indoor particle concentrations are of concern because it has been shown that people spend the majority of their time indoors. The Particle Total Exposure Assessment Methodolody (PTEAM) study/ detected an unexplained increase in personal exposure to PM10 when compared to concurrent stationary monitoring concentrations. This phenomenon has been termed the "personal cloud". The main objectives of this study were to: 1) compare personal, indoor, and outdoor PM concentrations; 2) further characterize the personal cloud - specifically, does wearing clothes elevate personal PM concentrations; and 3) determine the contribution of pets and other sources to indoor PM levels. In order to measure these effects, real-time continuous monitoring was conducted in an occupied home. In addition, a series of experiments were conducted to measure personal PM concentrations.
Methods. Four MIE Personal Data RAM nephelometers (MIE, Bedford, MA) and two to four Climet 500-i optical counters (Climet Instruments, Redlands, CA) were used to measure real-time indoor and outdoor PM concentrations at a Maryland residence for approximately two months. Particle concentrations were measured every five minutes by the Climet monitor, and every minute by the A41E monitor. The Climet monitors also measured temperature and relative humidity. The monitors were placed side-by-side whenever possible during data collection to allow for instrument comparison. To study the personal cloud, an MIE monitor was worn during home office work activities indoors.

Eight experiments were conducted to determine if clothes affect the magnitude of the personal cloud. In order to measure the differences between different levels of clothing, the experiments were conducted with the subject wearing either a bathing suit or light summer clothes.

Results. Median outdoor particle concentrations were 75 particles/cm3 compared to median indoor concentrations of 36 particles/cm 3 for particles ranging in size from 0.3 pm to 0.5 pm. Median outdoor particle concentrations for particles ranging in size from 5 -10 um were lower than median indoor levels. However, the mean indoor concentration of particles more than 10 um. was approximately twice the outdoor values.

Outdoor particle concentrations of 0.3 - 0.5 ~im particles had the highest correlation (Spearman r = 0.46, N = 25,280, p < 0.0001) with indoor concentrations in the living room. For particles > 5 fin, the outdoor concentrations were not adequate predictors of indoor concentrations.

Average personal PM concentrations at both levels of clothing were approximately 70% higher than concurrent stationary concentrations in the same room (p < 0.0001). A 6.2 p.g/m3 difference was detected between wearing summer clothes and a bathing suit for the personal PM concentrations (p <0.0014).

Average particle concentrations for particles in the 5 - 10 pm, and > 10 pan categories were calculated in three situations: when two Dalmatian dogs and two people were sleeping, when the dogs were alone in the house during the day, and when people and dogs were alone in the house during the day. The dog activities increased the levels of coarse particles (>5 pm) in the kitchen by 409%, living room by 48%, and outside near the monitor by 128%.

Conclusions. The average outdoor particle concentrations of 0.3 - 0.5 pm particles significantly exceeded average indoor concentrations. The observed increase in personal particle concentrations re-affirms the presence of the personal cloud. Furthermore, the PM difference observed between wearing light summer clothes and a bathing suit indicates that wearing clothes significantly increases the magnitude of the personal cloud. The presence of dogs significantly elevated PM levels (5 - 10 um, and > 10 um size ranges).

This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION A Predictive Model Relating Personal PM Exposures With Fixed Location Outdoor and Microenvironmental Indoor Concentrations 01/25/2000
Rodes, C. E., J. Thornburg, D. Ensor, P. A. Lawless, AND L. A. Wallace. A Predictive Model Relating Personal PM Exposures With Fixed Location Outdoor and Microenvironmental Indoor Concentrations. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The Atlanta Supersites project is the first of two Supersites projects to be established during Phase I of EPA's Supersites Program; Phase II is being established through a Request for Assistance. The other initial project is in Fresno, California. The Supersites Program is part of EPA's National PM2.5 network, which consists of about 1100 sites for PM2.5 mass measured by the FRM and about 250-300 sites where the major components of PM2.5 will be determined. The objectives of the Supersites Program are to obtain information on atmospheric processes and provide information to assist states with State Implementation Plans (SIPS) for PM2.5, to support health effects related studies, and to evaluate measurement methods for particulate matter (PM) and PM precursors. The Atlanta Supersites project is focused on the last of these objectives, but meets the other objectives through leveraging with ongoing studies, including the Southeastern Aerosol Research Characterization Study (SEARCH), Aerosol Research Inhalation Epidemiological Study (ARIES), Southern Center For the Integrated Study of Secondary Air Pollutants (SCISSAP), and others. Specifically, evaluations at Atlanta focused on state-of the science measurement methods for PM and PM precursors and related species. Methods evaluated as part of the Atlanta Supersite project included four single particle mass spectrometer type methods, a series of semicontinuous methods for mass, sulfate, nitrate, ammonium, gas phase counter parts and other related species, and integrated filter/denuder based methods for PM2.5 mass and the chemical components of mass. Sampling occurred over a 28 day period during the month of August at a SEARCH/AREIS site located in NE Atlanta. This paper will describe the objectives and design of the Atlanta Supersite project and present preliminary results, where available.
This work has been funded wholly or in part by the United States Environmental Protection Agency through internal funding. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION An Overview of EPA's Human Exposure Panel Studies 01/25/2000
Sheldon, L. S., R. W. Williams, V. R. Highsmith, C. E. Rodes, J. P. Creason, AND D. B. Walsh. An Overview of EPA's Human Exposure Panel Studies. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: In July 1997, the EPA Administrator issued new PM NAAQS that added PM2.5. The new standard is based largely on recent epidemiological investigations that indicated increased risks of mortality and morbidity are associated with higher concentrations of ambient particles. The new standard has been challenged largely due to inadequate information on toxicological mechanisms and actual human exposures to PM of ambient origin. In all of the epidemiological studies, ambient monitoring data were used as a surrogate for exposure. Previous studies with healthy individuals have shown poor correlations between ambient PM measurements and personal exposure.
The Clean Air Act mandates periodic reevaluations of the NAAQS. Thus the important scientific uncertainties associated with new standards must be addressed. For PM, this has required major new research initiatives. Congress requested an independent study by the National Research Council (NRC) to identify the most important research priorities and to develop a conceptual plan for PM research related to the new PM2.5 NAAQS. The NRC developed ten research recommendations. Two of the ten highest priority research activities are directed towards understanding PM exposures for susceptible subpopulations.

The PM Exposure Research Program for the National Exposure Research Laboratory (NERL) focuses directly on NRC Research Topic 1: Outdoor Measures versus Actual Human Exposure. Longitudinal panel studies are used to characterize interpersonal and intrapersonal variability in exposure to PM, and to describe the relationship between personal exposures to PM of ambient origin and ambient site measurements for susceptible subpopulations. This relationship is not clearly defined and represents a major uncertainty associated with the current standard. Specific objectives of the panel studies are:
1. To quantify personal exposures and indoor air concentrations for PM/gases for potentially
sensitive individuals;
2. To describe (magnitude and variability) the relationships between personal exposure, and indoor, outdoor and ambient air concentrations for PM/gases for different sensitive cohorts;
3. To examine the inter- and infra-personal variability in these relationships;
4. To identify and model the factors that contribute to the inter- and infra-personal variability in the relationships;
5. To determine the contribution of ambient concentrations to indoor air and personal exposures for PM/gases;
6. To examine the effects of airshed (location, season), population, and residential setting
(retirement center vs home) on these relationships.

Four projects are underway to evaluate different susceptible subpopulations, regions of the country, seasons, and housing stocks. Susceptible subpopulations will include COPD patients, individuals with cardiovascular disease, the elderly, asthmatics, and low SES elderly individuals. Three cooperative agreements have been awarded to Harvard University School of Public Health; New York University School of Medicine; and the University of Washington. NERL is conducting the fourth project which includes panel studies in Baltimore MD, Fresno CA, and RTP NC. An overview of the NERL project is given in Table 1.

The studies in Baltimore MD and Fresno CA have been completed and were conducted incollaboration with the U.S. EPA's National Health and Environmental Effects Research Laboratory. Generally, these studies have demonstrated the importance of housing type, house ventilation parameters, and personal behavior on exposure to total PM and PM of ambient origin. These studies confirmed that panel studies are feasible and that elderly populations will participate in personal PM monitoring studies over a long period of time (up to 28 days). Personal exposure monitoring and survey questionnaires were both practical and effective for understanding important exposure factors. Aggregate personal and residential PM measures showed high correlations with ambient site measures. Individual correlations showed more variability. Indoor/outdoor mass concentration ratios varied widely depending upon study site, season, residence and ventilation practices. Personal nepholometers provided valuable data on sources of personal exposure for PM. Concurrent real-time indoor and outdoor particle counts for different size fractions of PM were useful in evaluating penetration, decay, and emission parameters for PM. Results from these studies will be presented as various papers that address the program objectives. Results have also been used to refine the study design and approach for the studies in RTP. Data combined from all of the longitudinal panel studies will provide critical input for understanding and quantifying the relationship between personal exposure to ambient PM and ambient monitoring data.

This work has been funded wholly or in part by the U.S. Environmental Protection Agency under contract #68-DS-0040 to the Research Triangle Institute. It has be subjected to agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
PRESENTATION Personal Exposures to PM 2.5 Mass and Trace Elements in Baltimore, Maryland 01/25/2000
Landis, M. S., G. A. Norris, R. W. Williams, L. S. Sheldon, AND J. P. Creason. Personal Exposures to PM 2.5 Mass and Trace Elements in Baltimore, Maryland. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The relationship between a community monitor and personal exposures to PM2.5 mass and trace elements was investigated for 28 days during the summer of 1998 in a retirement home in Baltimore, Maryland. Daily community, outdoor and indoor PM2.5 were measured with a URG Versatile Air Pollutant Sampler (VAPS). In addition, daily personal and apartment PM2.5 samples were collected with a Marple Personal Exposure Monitor (PEM) for 10 subjects. Both the VAPS and PEM samples were analyzed with energy dispersive x-ray fluorescence (XRF). The spatial correlation coefficients between the community and outdoor monitor, and the species typically above the XRF detection for the VAPS samples. Infiltration of PM2.5 mass, and Sulfur were similar when determined with linear regression with factors of 0.35 (r2 = 0.94) and 0.39 (r2 = 0.94), respectively. Central indoor, apartment, and personal exposures were also evaluated. These results are compared to previous particulate matter exposure studies.
This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION Personal Exposure to Fine Particle Polycyclic Aromatic Hydrocarbons: Outdoor Source Tracers 01/25/2000
Lewtas, J., R. W. Williams, AND S. Wise. Personal Exposure to Fine Particle Polycyclic Aromatic Hydrocarbons: Outdoor Source Tracers. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Abstract: The most carcinogenic and toxic polycyclic aromatic hydrocarbons (PAH) are the 4-5 ring PAH found preferentially adsorbed to the fine particles (<2.54u in urban ambient air and personal air. Personal exposure to the carcinogenic particle bound PAH is also highly correlated with personal exposure to fine particles. Although combustion sources all emit PAH, it has long been recognized that PAH source profiles are characteristic of different sources. The underlying hypothesis of this study is that PAH profiles of personal exposure could serve as tracers of exposure to outdoor sources of particles, specifically combustion sources. This study examines the particulate PAH profile of personal exposures in three populations in the US, Japan, and Czech Republic (CZ) exposed to different PAH sources. Personal PAH profiles are compared to profiles of the major air pollution emission sources found in different geographic areas. benzo[ghi]perylene (BghiP) is identified as a source tracer for gasoline engine exhaust, a source found only in outdoor air, tunnels, and parking garages.

This work has been funded in part by the United States Protection Agency and has been subjected to Agency review and approved for publication.
PRESENTATION Wincadre (Computer-Aided Data Review and Evaluation) 03/11/2000
Coakley, W. A., L. C. Butler, V. D. Dandge, J. R. Caldwell, AND V. D. Desican. Wincadre (Computer-Aided Data Review and Evaluation). Presented at PITTCON 2000 Science for the 21st Century, New Orleans, LA, March 11-18, 2000.
Abstract: WinCADRE (Computer-Aided Data Review and Evaluation) is a Windows -based program designed for computer-assisted data validation. WinCADRE is a powerful tool which significantly decreases data validation turnaround time. The electronic-data-deliverable format has been designed in Excel, a widely-used, user-friendly spreadsheet program. WinCADRE reviews all data and checks laboratory calculations. WinCADRE data-review logic is based on the EPA Contract Laboratory Program (CLP)guidelines for data validation. However, the method, criteria, defects and flags are all customizable by the user for alternate CLP and non-CLP methods. This allows the user to customize method specifications, specify data review criteria, customize defect messages, and specify qualifier-flag assignments. The data are displayed from the file and are consolidated into customized user interface screens for added convenience. Reports are provided for import errors (missing and invalid), data listings [field samples, detection limits, analytical sequence, TIC (tentatively identified compound) results], analysis results (field samples, matrix spikes, post-digest spikes, duplicates, laboratory control samples, serial dilutions), and data review (data review, intermediate flag results, final flags spreadsheet). All reports may be previewed on-screen, printed as a hard copy, or saved to disk, allowing customization of the report formats.
This abstract has been subjected to Agency review and approved for publication.
PRESENTATION Comparison of Exercise Participation Rates for Children in the Literature With Those in EPA's Consolidated Human Activity Database (Chad) 10/24/2000
McCurdy, T. R. AND J. M. Burke. Comparison of Exercise Participation Rates for Children in the Literature With Those in EPA's Consolidated Human Activity Database (Chad). Presented at ISEA Conference, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: CHAD contains over 22,000 person-days of human activity pattern survey data. Part of the database includes exercise participation rates for children 0-17 years old, as well as for adults. Analyses of this database indicates that approximately 34% of the 0-17 age group (hereafter called "children") participates in "sports and exercise," and that the average number of minutes per day for "doers" is about 124 (2h). These results are approximate due to the various definitions of exercise used by the different studies that comprise CHAD. This paper examines the comparability of these rates with values reported in the wider exercise physiology and nutritional literature.
The categories normally used in that literature are "moderate," "moderate-to-vigorous," and "vigorous" physical activities (abbreviated MPA, MVPA, and VPA, respectively). For this comparison, we focus on the MVPA category. Since various authors use different levels of energy expenditure for MVPA, our comparison first had to develop a "consensus" definition of the level of energy used in MVPA, and then use it to develop exercise participation rates for children. Both nationally-applicable and site-specific exercise participation studies are used and compared.

The comparison indicates that children's exercise participation rate (% doers) and time spent in exercise by doers data in CHAD approximates that found in the national exercise surveys, and in many of the site-specific surveys of "normal" children. This finding does not hold for obese children, who exercise less often and less intensely than normals. Thus, users of CHAD can have a reasonable level of confidence regarding children's exercise participation rate information found in the database, at least for non-obese children, which is comforting given the importance of this activity in many exposure assessments of national ambient air quality standards--particularly ozone and sulfur dioxide.

This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION Carpet as a Sink for Chlorpyrifos Following the Use of Total Release Aerosols in the EPA Test House 07/17/2000
Mason, M. A., L. S. Sheldon, Z. Guo, AND D. M. Stout II. Carpet as a Sink for Chlorpyrifos Following the Use of Total Release Aerosols in the EPA Test House. Presented at Engineering Solutions to Indoor Air Quality Problems, Raleigh, NC, July 17-19, 2000.
Abstract: Pesticides may be found in homes from indoor applications to control pests or by their translocation from outdoor sources. Contaminants may persist adsorbed to surfaces and/or particles in "sinks" where over time they may dissociate as airborne vapors. Experiments were conducted to explore the relationship between the insecticide chlorpyrifos's distribution into carpet and carpet dust and it's reemission into air. An application using total release aerosols containing 0.5% chlorpyrifos was performed in the living room and den of the EPA test house. Afterwards the total deposition, total carpet extractable and total carpet dust extractable amounts were determined. In addition, over a two week period, air exchange rates and airborne concentrations were measured. Post-application sub-samples of carpeting were removed and placed in small environmental chambers (0.053 m3) to determine carpet emission factors. Findings show that airborne chlorpyrifos concentrations in the test house were initially highest in the living room and den (16 and 17 ug/m3) respectively) and declined to low levels by 14 days after application. Bedroom measurements immediately following the application were eleven times lower than the den and living room, reached maximal levels by day 2 (4.7 ug/m3) and declined to near parity by 14 days post-application. No stratification within rooms was observed. Total levels quantified from carpet and deposition coupons also showed the highest levels in rooms that received applications with negligible amounts in the bedroom. House dust levels measured for all rooms increased immediately following the application and remained above background through 14 days. Source emissions from carpet sub-samples in chamber studies suggest carpet is a latent source for the reemission of chlopryrifos into air following applications. However, inconsistencies in determining the mass balance make modeling and the calculation of emission factors difficult to interpret.
PRESENTATION Ambient Air Quality Monitoring 03/07/2000
Zweidinger, R. B. Ambient Air Quality Monitoring. Presented at International Workshop on Air Quality Management, Beijing, China, April 26-28, 2000.
Abstract: The primary objective of this workshop is to exchange information on available scientific bases for environmental regulatory decision making to senior Chinese decision-makers in a readily understandable format in order to expedite appropriate control measures in China. The Pollution Control Working Group of the China Council for International Cooperation on Environment and Development (CCICED-PCWG), in its April 1999 meeting agreed upon the urgent need to improve the effectiveness of this type of information exchange and technology transfer for enhanced protection of public health. In order to fill this need, a consensus was reached to conduct a series of briefing sessions for senior decision-makers in a workshop format in non-technical language. Particulate Matter (PM) regulation will be used as a case study since it serves as a good example of the necessity for comprehensive, well-organized, and timely information exchange. In this workshop, the Chinese will describe the current state of air pollution control in China, and senior US officials and European experts will describe advances made in PM regulations over the last three decades. Presentations by EPA's NERL representative to the workshop will cover ambient air quality monitoring (instrumentation, evaluation of measurement methods, sampling and analysis) and human exposure assessment: indoor & outdoor.
This paper has been reviewed in accordance with the U.S. Environmental Protection Agency peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Tyrosinase-Based Carbon Paste Electrode Biosensor for Detection of Phenols: Binder and Pre-Oxidation Effects 07/02/2000
Rogers, K. R., J. Y. Becker, AND J. Cembrano. Tyrosinase-Based Carbon Paste Electrode Biosensor for Detection of Phenols: Binder and Pre-Oxidation Effects. Presented at 8th International Meeting on Chemical Sensors, Basel, Switzerland, July 2-5, 2000.
Abstract: Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil or paraffin wax oil yielded a greater response to phenol and catechol than those using the higher viscosity oils of similar chemical composition. Despite its relatively high viscosity, the use of silicone oil Si PS 086 as carbon paste binder resulted in a 2 fold increase over the silicone oil Si AR 200 and a 4-6 fold increase (over electrodes using mineral oils) in responses to phenol, p-chlorophenol, and p-cresol. Carbon paste electrodes using a series of (DC200) silicone oils ranging in viscosity from 10 to 60,000 mPa.s were constructed and evaluated. A significantly enhanced response was observed using a binder of intermediate viscosity (100 mPa.s). Also reported is the enhanced enzyme electrode response to phenol and catechol resulting from pre-oxidation of these substrates using a plain carbon paste electrode in a series (in-line) dual electrode configuration.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by EPA.
PRESENTATION Electrochemical Technique for Tnt Using Disposable Screen-Printed Electrode 07/02/2000
Rogers, K. R. AND R. Pearson. Electrochemical Technique for Tnt Using Disposable Screen-Printed Electrode. Presented at 8th International Meeting on Chemical Sensors, Basel, Switzerland, July 2-5, 2000.
Abstract: Screen-printed thick film electrodes are demonstrated as voltammetric sensors for measurement of 2,4,6-trinitrotoluene (TNT). The square wave voltammetric (SWV) scan technique is used to measure TNT in as little as 50 uL sample volumes. This electrochemical assay is coupled with a solid phase extraction (SPE) protocol using 3M Empore SDB-RPS membranes. The explosive is extracted from the membrane using acetonitrile, which showed little effect on the assay at a final concentration of 10%. The coupling of SPE and SWV with the use of disposable electrodes results in a dynamic assay range of 2 ppb to 2 ppm for TNT. The application of this method to environmental samples will also be discussed. The simplicity, rapidity, cost-effectiveness and sensitivity of this assay make it an excellent candidate for development as a field analytical method.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by EPA.
PRESENTATION Detection of Low Dose Radiation-and Chemically-Induced Dna Damage Using Temperature Differential Fluorescence Assays 07/02/2000
Rogers, K. R., A. B. Apostol, O. S. Madsen, AND C. W. Spencer. Detection of Low Dose Radiation-and Chemically-Induced Dna Damage Using Temperature Differential Fluorescence Assays. Presented at 8th International Meeting on Chemical Sensors, Basel, Switzerland, July 2-5, 2000.
Abstract: Rapid, sensitive and simple assays for radiation- and chemically-induced DNA damage can be of significant benefit to a number of fields including radiation biology, clinical research, and environmental monitoring. Although temperature-induced DNA strand separation has been used as an indicator of oxidative DNA damage and single strand breaks, recent advances in double strand-specific dyes and fiber optic biosensor techniques form the basis for improvements in these assays. Rapid and sensitive biosensor and optical screening assays that measure DNA damage resulting from chemical exposure or low dose radiation are reported. For the fiber optic biosensor assay, a biotin-labeled capture oligonucleotide (38 mer) was immobilized to an avidin-coated quartz fiber. Hybridization of a dye-labeled complementary sequence was observed using the evanescent wave and reported at the proximal end of the optical fiber. Changes in temperature-induced strand separation were then used as a sensitive indicator of DNA damage resulting from exposure of the dye-labeled strand to either SIN-1 (3-morpholinosydnonimine, a source of OH- radicals) or low doses of ionizing radiation. For the optical screening assay, changes in temperature induced strand separation in both calf thymus DNA and plasmid DNA (puc 19 plasmid from E. coli) were measured after exposure to low doses of ionizing radiation (0.004 to 1 Gray). The double strand sensitive dye PicoGreen was used as an indicator of DNA denaturation. Calibration plots indicate that fluorescence changes corresponding to amounts as low as 1 ng double stranded DNA (106 copies for plasmid puc19) are detected by this method.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by EPA.
PRESENTATION Implications of the US Clean Air Act on the Future of Urban Air Quality: Linking Urban Air, Indoor Environments and Human Exposure 04/16/2000
Cupitt, L. T. Implications of the US Clean Air Act on the Future of Urban Air Quality: Linking Urban Air, Indoor Environments and Human Exposure. Presented at Urban Air, Indoor Environment and Human Exposure: Future Needs for Policy-Science Interface, Thessaloniki, Greece, April 16-18, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Immunochemistry at the U.S. EPA, National Exposure Research Laboratory's Human Exposure Research Branch 05/09/2000
Van Emon, J. M. Immunochemistry at the U.S. EPA, National Exposure Research Laboratory's Human Exposure Research Branch. Presented at EnvironAnalysis 2000, Ontario, Canada, May 9-11, 2000.
Abstract: The HERB has developed several immunoassay methods for environmental and human exposure studies. Immunoassays to detect low levels (<10 ng/mL) chlorpyrifos in food, track-in dirt and house dust have been developed for dietary and indoor exposure surveys. An immunoassay for the urinary metabolite of chlorpyrifos, 3,5,6-trichloro-2-pyridinol (TCP) has been optimized and evaluated using real-world samples from several monitoring studies. Comparative studies with GC/MS indicate a good correlation with the TCP assay. Antibodies to detect O,O-diethyl thionates/thionothiolates have been developed and characterized for multiple organophosphorous pesticides (e.g., ethyl parathion, coumaphos, diazinon). These antibodies were characterized in several ELISAs as an approach for the class detection of organophosphorus pesticides. An immunoassay for polychlorinated biphenyls (PCBs) suitable for several soil matrices was developed for hazardous waste site monitoring and evaluated at EPA Superfund sites. The detection limits for Aroclors 1242 and 1248 in soil are 10.5 and 9 ng/g, respectively. The use of conducting polymer-based immunoassay techniques in environmental monitoring has also been investigated. Specific antibody immobilized onto conducting electroactive polymers (CEPs), in combination with a pulsed potential waveform, enables selective molecular recognition. A CEP-antibody immunosensor for PCB, had a linear dynamic range of 0.3-100 ng/mL. We have also demonstrated the use of immunoaffinity capillary electrochromatography (CEC) to perform on-line selective trace enrichment of analytes prior to capillary zone electrophoresis. These studies illustrate how immunochemical methods can respond to the needs of various monitoring programs.
The U.S. Environmental Protection Agency (U.S.EPA) through its Office of Research and Development (ORD) funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Performance and Sensitivity Analysis of the USEPA Wins Fractionator for the PM 2.5 Federal Reference Method 01/25/2000
Vanderpool, R. W., T. M. Peters, S. Natarajan, D. B. Gemmill, AND R. W. Wiener. Performance and Sensitivity Analysis of the USEPA Wins Fractionator for the PM 2.5 Federal Reference Method. Presented at PM 2000 AWMA Conference, Charleston, SC, January 25-28, 2000.
Abstract: In response to growing health concerns related to atmospheric fine particles, EPA promulgated in 1997 a new particulate matter standard accompanied by new sampling methodology. Based on a review of pertinent literature, a new metric (PM;,) was adopted and its measurement method was specified as a 24 hour, integrated sample whose concentration was to be determined gravimetrically. The new method was developed as a hybrid of design and performance specifications. Components designed to representatively extract, size-select, and transport the PM^ aerosol (inlet, downtube, fractionator, and upper portion of the filter holder) were all specified by design with mechanical drawings published in the CFR. Accuracy and precision of flow control, ambient temperature and pressure measurement, and allowable sample overheat were all specified by performance. Accurate fractionation of aspirated atmospheric aerosol is a critical feature of the measurement method. In the FRM sampler, this fractionation is provided by a single-stage, single-jet impactor known as the WINS (Well Impactor Ninety-Six). Particles larger than 2.5 um aerodynamic diameter are efficiently collected on a glass fiber filter immersed in a low-volatility diffusion oil. Particles smaller than 2.5 um are transported to a teflon afterfilter for subsequent gravimetric measurement.
This work was funded by the U.S. EPA through its Office of Research and Development under contract #68-D5-0040 to Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Determination of Particle Deposition Rates for Cooking and Other Indoor Source 11/06/2000
HowardReed, C., L. A. Wallace, AND S. J. Emmerich. Determination of Particle Deposition Rates for Cooking and Other Indoor Source. Presented at 19th Annual AAAR Conference, St. Louis, MO, November 6-10, 2000.
Abstract: Residential indoor particle concentrations are dependent on indoor sources, penetration of outdoor particles, air change with outdoors, and deposition of particles on indoor surfaces as well as other loss mechanisms. Of these factors, few data are available on deposition of particles generated indoors (e.g., from cooking or cleaning sources). To increase the knowledge base related to the deposition of particles of indoor origin, a one-year continuous particle and air change rate monitoring study was completed in an occupied home in Reston, VA.
Indoor concentrations or particles, ranging in size from 0.01 um to 20 um, were continuously measured with several "real-time" instruments, including: a Scanning Mobility Particle Sizer (SMPS; TSI, Inc.), an Aerodynamic Particle Sizer (APS; TSI, Inc.), and an Aethalometer (Magee Scientific). Particle concentrations were also measured in multiple locations within the house using other continuous instruments: 2 to 4 Climets (Climet Instruments), 2 to 4 personal DataRams (MIE, Inc.), and two PAH monitors (Ecochem, Inc.). To determine air change rates, a gas chromatograph with electron capture detector (GC/ECD) was used to measure the decay of SF6 in multiple locations within the house.

Sources that contributed the largest number of particles in this non-smoking home were combustion activities (e.g., candles, matches, incense), cooking activities (e.g., frying, sauteeing, broiling, and stir-frying), and cleaning activities (e.g., changing cat's litter box). During these events, indoor particle concentrations for all size categories measured (depending on source) increased to levels significantly higher (one to three orders of magnitude) than those measured outdoors. As a result, particle deposition rates may be directly solved with a mass balance model. Particle deposition rates tended to follow the theoretical "U-shaped" curve for increasing particle size. Initial estimates of deposition rates range from 3.5 h-1 to 0.4 h-1 for particles from 0.01 um to 0.5 um and 0.4 h-1 to 5 h-1 for particles from 0.5 um to 7 um. Using measured deposition rates for multiple particle sizes and associated theoretical deposition velocities, effective contact surface area to volume ratios for this house will also be calculated. The results from this study have the potential to improve modeling of indoor air particles.

The research described in this abstract has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Soa Yields and Organic Product Distribution from Natural Hydrocarbon/NOx Irradiations 11/06/2000
Conver, T. S., T. E. Kleindienst, W. Li, C. D. McIver, E. W. Corse, AND E. O. Edney. Soa Yields and Organic Product Distribution from Natural Hydrocarbon/NOx Irradiations. Presented at 19th Annual AAAR Conference, St. Louis, MO, November 6-10, 2000.
Abstract: Secondary organic aerosol (SOA) typically comprises one-quarter to one-third of the ambient aerosol mass in summertime urban atmospheres. In tropospheric environments, the main precursors of SOA come from aromatic and natural hydrocarbons. Recent work by various investigators have begun to provide a quantitative basis for establishing reaction yields and speciation of SOA.
A laboratory system has been developed to investigate SOA formation and composition under highly controlled conditions. For this work, two laboratory chamber systems were used. The first is based on a 9 cubic meter all-Teflon chamber operated in a static mode and the second on an 11.3 cubic meter, Teflon-lined smog chamber operated in a dynamic mode. SOA products from the NOX-mediated photooxidations of a-pinene, b-pinene, d-limonene, and delta-carene were generated. Chamber conditions were set to ensure that extensive secondary gas-phase chemistry occurred. Under these conditions, nucleation of the oxidized mixture occurred. Particles size and volume distributions were measured during the irradiation using a scanning mobility particle sizer. These measurements suggest that particle formation occurs before a substantial ozone concentration is generated in the chamber. SOA yield were measured from organic carbon measurements of 24-h quartz filter collections and the mass of reacted hydrocarbon. These measurements used carbon-based and extractable XAD denuders minimize filter artifacts.

Organic aerosol from the NOX irradiations was also collected on Zefluor filters and extracted for analysis of individual compounds. Derivatization techniques were used to classify and identify specific products formed in SOA. Since many of the products are expected to be semivolatile, XAD denuders were used to study the gas-aerosol partitioning. Comparisons will be made between the products formed in these systems with those reported for the ozone-natural hydrocarbon reactions.

The U.S. Environmental Protection Agency through its Office of Research and Development funded and collaborated in the research described here (Contract 68D5-0049 with ManTech Environmental Technology, Inc.). It has been subjected to Agency review and approved for publication.
PRESENTATION Radiocarbon Analysis of PM 2.5 Ambient Aerosol 03/06/2000
Lewis, C. W., L. Stockburger, G. A. Klouda, W. D. Ellenson, AND C. R. Fortune. Radiocarbon Analysis of PM 2.5 Ambient Aerosol. Presented at SOS Data Analysis Workshop 2000, Research Triangle Park, NC, March 6-10, 2000.
Abstract: The radiocarbon (14C) content of an ambient aerosol sample can be directly related to the fraction of the sample's total carbon mass contributed by natural (biogenic) sources. Such knowledge is difficult to determine by other means, and important for devising ambient PM control strategies. During the SOS Nashville 99 field study, forty-five PM-2.5 quartz-filter samples were collected at Cornelia Fort Airport for subsequent radiocarbon analysis. Two samplers were operated concurrently, at 100 and 300 L min-1. Samples were collected during both day and night, mostly over 11.5-h sampling durations, but some over 5.5-h periods. Samples were collected both with and without an upstream semi-volatile organic compounds (SVOC) denuder to gain information on the possible presence of positive organic sampling artifact. The organic carbon (OC) and elemental carbon (EC) content of the samples have been quantified by the Thermal-Optical Transmittance method. Samples will be prepared for radiocarbon analysis both with and without solvent (dichloromethane) extraction. Sample preparation is proceeding.
PRESENTATION The Speciation and Distribution of Vocs in the Nashville Urban Area 03/06/2000
Lonneman, W. A. The Speciation and Distribution of Vocs in the Nashville Urban Area. Presented at SOS Data Analysis Workshop 2000, Research Triangle Park, NC, March 6-10, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Aerosol Size Distribution and Chemical Speciation of Cornella Fort Airport: Nashville 99 Sos 03/06/2000
Stockburger, L. Aerosol Size Distribution and Chemical Speciation of Cornella Fort Airport: Nashville 99 Sos. Presented at SOS Data Analysis Workshop 2000, Research Triangle Park, NC, March 6-10, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Ambient Monitoring of Hcho at the Polk Bldg. Nashville, Tn Sos '99 Study 03/06/2000
McClenny, W. A., J. Rice, AND P. Klotz. Ambient Monitoring of Hcho at the Polk Bldg. Nashville, Tn Sos '99 Study. Presented at SOS Data Analysis Workshop 2000, Research Triangle Park, NC, March 6-10, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Preliminary Results of VOC Analyses By Auto Gc/MS at Cornelia Fort Airpark June 15-July 15, 1999 03/06/2000
Oliver, K. D., H. H. Jacumin Jr., K. G. Kronmiller, E. H. Daughtrey Jr., AND W. A. McClenny. Preliminary Results of VOC Analyses By Auto Gc/MS at Cornelia Fort Airpark June 15-July 15, 1999. Presented at SOS Data Analysis Workshop 2000, Research Triangle Park, NC, March 6-10, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION NOx/Noy Monitoring Using Modified/Unmodified Commercial Instrumentation 03/06/2000
Kronmiller, K. G., M. L. Wheeler, E. H. Daughtrey Jr., AND W. A. McClenny. NOx/Noy Monitoring Using Modified/Unmodified Commercial Instrumentation. Presented at SOS Data Analysis Workshop 2000, Research Triangle Park, NC, March 6-10, 2000.
Abstract: Three systems were used for monitoring oxides of nitrogen (NO, NO2, Noy, at the Cornelia Fort Airpark site in the 1999 Southern Oxidant Study near Nashville, TN during the months of June and July. Of the three systems, one was an unmodified ultraviolet differential optical absorption spectrometer (UV-DOAS) instrument manufactured by OPSIS AB (Furuland, Sweden) configured to measure NO2. The second system was a standard chemiluminescence type oxides of nitrogen analyzer manufactured by Thermo Instruments (model Tei42, Franklin, MA) modified with an automated flow controller so that ambient air passed through either a standard heated molybdenum converter, a chromium trioxide converter or an unaffected pathway. This system also included a luminol based chemiluminescence analyzer (LMA3, Unisearch, Toronto, Canada) sampling the same air as the TEI42 monitor from a common manifold. The third system used was a modified chemiluminescence monitor which, in addition to the standard heated molybdenum converter, used a prototype NO2 photolytic cell for a direct measurement of NO2, unlike standard chemiluminescence Nox monitors which derive NO2 by a mathematical subtraction of the NO value from the Noy value. This instrument thus provided NO2 by photolysis as well as direct NO and Noy measurements. The standard instrument (model Tei42C, Thermo Instruments) was modified by the manufacturer to include additional sampling, controls and firmware revisions to permit the use of photolytic converter.
PRESENTATION Sources of Variability in Sample Collection and Preparation for Surfaces With Lead Coatings 08/20/2000
Harper, S. L. AND W. F. Gutknecht. Sources of Variability in Sample Collection and Preparation for Surfaces With Lead Coatings. Presented at 220th American Chemical Society National Meeting, Washington, DC, August 20-25, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Incorporation of Real-Time Methods Into US EPA Laboratory Procedures for Evaluation of Size Selective Samplers 09/04/2000
Peters, T. M., R. W. Vanderpool, AND R. W. Wiener. Incorporation of Real-Time Methods Into US EPA Laboratory Procedures for Evaluation of Size Selective Samplers. Presented at European Aerosol Conference, Dublin, Ireland, September 4-8, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Exposure Analysis Methods Used in Environmental Risk Assessment 03/27/2000
Ozkaynak, A. H. Exposure Analysis Methods Used in Environmental Risk Assessment. Presented at Israel/EPA Comparative Risk Meeting, Tel Aviv, Israel, March 27, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Characterization of Emissions from Hand-Held Two-Stroke Engines 06/01/2000
Gabele, P. A. Characterization of Emissions from Hand-Held Two-Stroke Engines. Presented at 93rd Annual AWMA Conference, Salt Lake City, UT, June 18-22, 2000.
Abstract: Despite their extremely high organic and particulate matter emission rates, two-stroke engines remain among the least studied of engine types. Such studies are rare because they are costly to perform. Results reported in this paper were obtained using a facility that shares exhaust emission sampling and analytical systems with an adjacent emissions test laboratory. This enabled a comprehensive examination of emissions from three hand-held, two-stroke, engines. In addition to the determination of routine regulated pollutant emission rates, organic emissions are speciated and particulate matter emission rates are measured. Each engine was tested using two fuels: 1990 Baseline Gasoline and a reformulated gasoline. One engine was run for an extended period to assess durability effects on exhaust emissions, and another was operated at a leaner air-fuel ratio setting to examine enleanment effects. In the durability testing, organic and particulate matter emissions actually appear to decrease slightly with increased operating time. In the enleanment test, organic and carbon monoxide emission rates decreased significantly, as expected, with the increase in air-fuel ratio. Large decreases in particulate matter also ensued. Fuel selection strongly influenced composition of organic emissions. With reformulated gasoline, aggregate toxic and ozone potential emissions were consistently lower compared to emissions with the Baseline fuel.
The information in this paper has been funded by the Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Relationships of Gaseous Concentrations of Criteria Air Pollutants and PM 2.5 Measures 09/12/2000
Williams, R. W., J. C. Suggs, L. S. Sheldon, G. F. Evans, J. P. Creason, C. E. Rodes, AND P. A. Lawless. Relationships of Gaseous Concentrations of Criteria Air Pollutants and PM 2.5 Measures. Presented at EPA/AWMA International Symposium on the Measurement of Toxic and Related Air Pollutants, Research Triangle Park, NC, September 12-14, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Optimization of High-Speed Gc/Tofms for Method to-14 Analysis 09/12/2000
Berkley, R. E., M. L. Akard, K. D. Oliver, H. H. Jacumin Jr., P. Ebersold, AND T. Budd. Optimization of High-Speed Gc/Tofms for Method to-14 Analysis. Presented at EPA/AWMA Symposium, Research Triangle Park, NC, September 12-14, 2000.
Abstract: A fast GC/MS system (FGCMS) consisting of a high-speed gas chromatograph equipped with a narrow bandwidth injection accessory and a time-of-flight mass spectrometer detector is being optimized for analysis of Method TO-14 target compounds. The system consists entirely of commercially-available components. Turn-around time between sample injections has been reduced to six minutes, in contrast to an hour for conventional Method TO-14. Instrument configuration, control, and data processing procedures under development are described.
The information in this document has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Optimization of High-Speed Gc/Tofms for Method to-14 Analysis 09/12/2000
Berkley, R. E., M. L. Akard, B. D. Gardner, K. D. Oliver, AND H. H. Jacumin Jr. Optimization of High-Speed Gc/Tofms for Method to-14 Analysis. Presented at EPA/AWMA Symposium, Research Triangle Park, NC, September 12-14, 2000.
Abstract: A fast GC/MS system (FGCMS) consisting of a high-speed gas chromatograph equipped with a narrow bandwidth injection accessory and a time-of-flight mass spectrometer detector is being optimized for analysis of Method TO-14 target compounds. The system consists entirely of commercially-available components. Turn-around time between sample injections has been reduced to six minutes, in contrast to an hour for conventional Method TO-14. Instrument configuration, control, and data processing procedures under development are described.
The information in this document has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Evaluation of a Personal Nephelometer for Human Exposure Monitoring 09/12/2000
Rea, A. W., F. Martin III, AND W. J. Mitchell. Evaluation of a Personal Nephelometer for Human Exposure Monitoring. Presented at EPA/AWMA Symposium, Research Triangle Park, NC, September 12-14, 2000.
Abstract: Current particulate matter (PM) exposure studies are using continuous personal nephelometers (pDR-1000, MIE, Inc.) to measure human exposure to PM. The personal nephelometer is a passive sampler which uses light scattering technology to measure particles ranging in size from 0.1-10 um using a light scattering technique, however, it is more responsive to particles in the fine particle size range (0.3 - 2 um). While the data from the nephelometer remain semi-quantitative, the instrument is very useful for identifying activities and microenvironments that may significantly enhance human exposure to PM. Based on the use of this instrument in the field, we recognize that it is important to identify activities or environments that may have an adverse effect on the instrument's response and subsequent data quality. We have tested the nephelometers response to sample vest fabric (cotton/polyester or nylon), sampler location on an individual (shoulder vs. waist), and relative humidity. Repeated scripted activities while wearing a 50-50 cotton/polyester or a nylon vest indicated that significantly more particles (p < 0.01) were introduced by the cotton/polyester vest than the nylon vest. The location of the monitor was weakly significantly different (p < 0.1) for many common activities, and significantly higher particle readings were observed at the waist (p < 0.02) while sweeping. After being exposed to relative humidity levels ranging from 40% to 90% at 21o C and from 40% to 60% relative humidity at 32o C, monitors equilibrated with stationary monitors within 2 to 3 minutes. Recovery took 5 to 15 minutes at relative humidity ranging from 80% to 85% at 32o C. Some monitors had problems recovering after being exposed to 90% relative humidity (32o C). Although some activities appeared to affect the response of the nephelometer, they were easily identified and the overall data quality was not likely to be compromised.
This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Average Annual Solar UV Dose of the Continental US Citizen 07/02/2000
Godar, D. E., S. P. Wengraitis, J. H. Shreffler, AND D. Sliney. Average Annual Solar UV Dose of the Continental US Citizen. Presented at 13th International Congress on Photobiology, San Francisco, CA, July 2-6, 2000.
Abstract: The average annual solar UV dose of US citizens is not known, but is required for relative risk assessments of skin cancer from UV-emitting devices. We solved this problem using a novel approach. The EPA's "National Human Activity Pattern Survey" recorded the daily outdoor-activity profiles over the course of two years for about 10,000 continental US citizens to assess exposure to environmental pollutants, one of which is UV radiation. From that survey, we extracted only the daylight-hour data of the northern and southern indoor workers subdividing by seasons, sex, and age (0-21, 22-59, and 60+) to find the average time Americans spend outdoors in each group. Using the ambient percentage for indoor workers found by the Dutch (2.5%; H. Slaper thesis, 1987) to standardize our northeastern data, we found their actual UV-exposure time was about one-third their total daylight-time outdoors. Of the total available solar UV, the average US citizen's ambient percentages are as follows: northern females 2.67% and males 3.54%, southern females 2.56% and males 3.79%. We then calculated their average annual solar UV dose, excluding vacation, using seasonal averages from measurements made over two years by EPA Brewer spectrophotometers located in the four quadrants of the US: Atlanta, GA, Boston, MA, Bozeman, MT and Riverside, CA. Including a conservative three-week vacation in the continental US, i.e., 30% country, 30 % beach, 30% sight-seeing and 10% home, the estimated average annual solar UV doses are as follows: northern females 28,361 J/m2 and males 32,479 J/m2, southern females 33,215 J/m2 and males 39,834 J/m2. The average annual solar UV dose for the continental US citizen is 25,169 + vacation (9,178), or 34,347 J/m2 (343 SED or 137 MED, MED=250 J/m2). Thus, we can now assess the relative increased risk of skin cancer from UV-emitting devices for the continental US citizen.
This work has been funded in part by the United States Environmental Protection Agency. It has been subjected to Agency Review and approved for publication.
PRESENTATION Agricultural Health Study/Pesticide Exposure Study Design 08/20/2000
Thomas, K. W., L. S. Sheldon, W. C. Steen, M. R. Alavanja, A. Blair, M. Dosemeci, AND D. P. Sandler. Agricultural Health Study/Pesticide Exposure Study Design. Presented at American Chemical Society National Meeting, Washington, DC, August 20-24, 2000.
Abstract: The Agricultural Health Study (AHS) is a prospective epidemiologic study of a large cohort of pesticide applicators and their spouses in Iowa and North Carolina. The Pesticide Exposure Study is a sub-study to evaluate exposure factors and to provide data to assess exposure classification procedures. Exposure to two applied pesticides (2,4-D and chlorpyrifos) will be measured for up to 160 applicators and their families. Applicators are selected based on application methods and uses of personal protective equipment of interest for the epidemiological study cohort. Two exposure measurement approaches are being employed: a) a combination of dermal patch, hand wipe, and personal air measurements collected during an observed handling, mixing, loading, and application (HMLA) and, b) urinary biomarker measurements from samples collected in the morning before and at two time intervals after the observed HMLA. A target goal of monitoring for 28 applicators was set for Year 1 work in Iowa; however, only 10 applicators were monitored due to scheduling delays and an early planting season. Participation information and pesticide use data are provided for Year 1 monitoring participants. Preliminary measurement results will be shown for Year 1 monitoring, including examples of dermal sample concentrations and urine concentrations for for applicators and family members. The study will continue in Year 2 in Iowa and North Carolina, with a goal of monitoring 70 applicators and repeat monitoring for 10 applicators. Current participation information is provided for Year 2 screening and recruitment to date.
This work has been funded in part by the U.S. Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names of commercial products does not constitute endorsement or recommendation for use.
PRESENTATION A Feasibility Study Examining the Potential for Human Exposure to Pet-Borne Diazinon Residues Following Residential Turf Applications 08/20/2000
Stout II, D. M., M. K. Morgan, AND N. K. Wilson. A Feasibility Study Examining the Potential for Human Exposure to Pet-Borne Diazinon Residues Following Residential Turf Applications. Presented at American Chemical Society National Meeting, Washington, DC, August 20-24, 2000.
Abstract: The domestic dog may be a vehicle for translocation of pesticide residues following residential applications to turf. In addition, human occupants may be exposed to residues deposited inside homes by pets or by intimate contacts with them. This study examines the potential of an indoor/outdoor, high activity dog to transport insecticide residues physically into a residence after an application of a granular diazinon formulation to the lawn. A family of four with a high activity indoor/outdoor dog, who intended to apply granular diazinon to their lawn, was recruited to participate. Samples were collected approximately three hours before application and on days 0, 3, 9, and 15 after application. Family members completed time-activity diaries recording their general daily activities at the residence. Measurements made outside the house included a sample of diazinon formulation that was applied, deposition samples over the treated area, soil, turf transferable residues, and entryway deposits on a doormat. Inside the home, airborne residues and HVS3 vacuum sweepings were collected in the living room. Hand wipes were collected from the mother and her two children. Fur clippings, fur wipes, and paw wipes were collected from the dog. The soil, turf transferable residues, and doormat levels were initially increased over pre-application levels, but declined substantially by day 15. Indoor air concentrations of diazinon also increased above background levels after application. The mother and one child had levels of residues above background on their hands on days 0, 3, 9, and 15 post-application. Residues above background levels were present on the dog's paws and fur on days 0, 3, 9, and 15 post-application. These results suggest that dogs may transfer pesticides into homes following lawn applications. Additional studies are planned to clarify further the role of pet dogs in translocating residues and the resulting potential for human exposure.
This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION A Feasibility Study Examining the Potential for Human Health Exposure to Pet-Borne Diazinon Residues Following Residential Turf Applications 10/24/2000
Morgan, M. K., D. M. Stout II, AND N. K. Wilson. A Feasibility Study Examining the Potential for Human Health Exposure to Pet-Borne Diazinon Residues Following Residential Turf Applications. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: The domestic dog may be a vehicle for translocation of pesticide residues following residential applications to turf. In addition, human occupants may be exposed to residues deposited inside homes by pets or by intimate contacts with them. This study examines the potential of an indoor/outdoor, high activity dog to transport insecticide residues physically into a residence after an application of a granular diazinon formulation to the lawn. A family of four with a high activity indoor/outdoor dog, who intended to apply granular diazinon to their lawn, was recruited to participate. Samples were collected approximately three hours before application and on days 0, 3, 9, and 15 after application. Family members completed time-activity diaries recording their general daily activities at the residence. Measurements made outside the house included a sample of diazinon formulation that was applied, deposition samples over the treated area, soil, turf transferable residues, and entryway deposits on a doormat. Inside the home, airborne residues and HVS3 vacuum sweepings were collected in the living room. Hand wipes were collected from the mother and her two children. Fur clippings, fur wipes, and paw wipes were collected from the dog. The soil, turf transferable residues, and doormat levels were initially increased over pre-application levels, but declined substantially by day 15. Indoor air concentrations of diazinon also increased above background levels after application. The mother and one child had levels of residues above background on their hands on days 0, 3, 9, and 15 post-application. Residues above background levels were present on the dog's paws and fur on days 0, 3, 9, and 15 post-application. These results suggest that dogs may transfer pesticides into homes following lawn applications. Additional studies are planned to clarify further the role of pet dogs in translocating residues and the resulting potential for human exposure.
This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION Studies of Preschool Children's Exposures to Persistent Pesticides 08/20/2000
Wilson, N. K., J. C. Chuang, AND C. Lyu. Studies of Preschool Children's Exposures to Persistent Pesticides. Presented at National Meeting of the American Chemical Society, Washington, DC, August 20-24, 2000.
Abstract: Young children may have greater exposures than do older children or adults to some persistent organic pesticides, because of differences in their diet and activities. The physical impact of those exposures may also be increased by their small body size, immature body systems, and rapid development. In two small studies examining the potential for exposure to persistent organic pollutants of preschool children who attend child day care centers, we found that the pathways for exposure differed with compound class and with environmental medium. We calculated aggregate exposures from the various environmental media: indoor and outdoor air, house dust, play area soil, and diet. For these children, dietary ingestion was the major pathway for many of the pesticide compounds, including several organochlorines (OC) such as DDT or chlordane, the organophosphates (OP) chlorpyrifos and diazinon, and the herbicide 2,4-D, although inhalation was also important for the OP and OC. Nondietary ingestion also contributed to the sub-acute and chronic exposures of these children. None of the potential doses calculated from the exposures exceeded the established reference doses (RfD). To understand these exposures and confirm our small study findings, we are now doing a larger research study of approximately 260 children. This larger study, Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP), was initiated in early 2000, with field sampling in North Carolina and Ohio planned to being in July 2000.
This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION Ctepp Overview: A Pilot Study of Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants 10/24/2000
Wilson, N. K., G. F. Evans, J. C. Chuang, AND C. Lyu. Ctepp Overview: A Pilot Study of Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants. Presented at International Society of Exposure Analysis, Monterey, CA, October 24-27, 2000.
Abstract: The research study, "Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants," (CTEPP) is a pilot-scale project involving about 260 children in their everyday surroundings. The objectives of CTEPP are twofold: (1) To measure the aggregate exposure through multiple pathways of a set of preschool children in several North Carolina and Ohio counties to a suite of persistent pollutants in their everyday environments, and (2) To apportion the exposure pathways and to identify and formulate the important hypotheses to be tested in future research.
The targeted compounds are persistent in the indoor and sometimes the outdoor environments, so that very low levels may exist and provide a source of chronic, non-acute exposure. Targeted pollutants include polycyclic aromatic hydrocarbons; chlorinated, carbamate, triazine, pyrethroid and organophosphate pesticides; phthalate esters; phenols; and polychlorinated biphenyls.

Children who stay at home with an adult caregiver and children who attend preschool or day care are included. Emphasis is on children ages 18 months to 4 years. Exposures of the children and their primary adult caregivers living in the same household are estimated through the collection and analysis of samples of food, beverages, and drinking water; indoor and outdoor air; hand wipes; house dust, classroom dust, and play area soil; smooth floor and food preparation surface wipes; and urine. Children's activity and food diaries during the sampling period are maintained by the parent/teachers. Approximately 10% of the children are videotaped for two hours during the sampling to supplement the activity diaries and observations.

The CTEPP study was initiated in early 2000, with field sampling in NC and OH planned to begin in July 2000. Sample collection in the targeted NC and OH counties and subsequent analysis will extend over a two year period.

This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION Overview of EPA's Human Exposure and Source-to-Dose Modeling Program: Headsup 10/24/2000
Ozkaynak, A. H., G. F. Evans, D. A. Pahl, AND J. A. Graham. Overview of EPA's Human Exposure and Source-to-Dose Modeling Program: Headsup. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: EPA's human exposure and source-to-dose modeling program is designed to provide a scientifically sound approach to understanding how people are actually exposed to pollutants and the magnitude of predicted exposures and dose. The objective of this research project is to develop a comprehensive human exposure source-to-dose (HES2D) model that can estimate multimedia, multi pathway human exposures and doses to both the general population and to identifiable susceptible subpopulations. The HES2D modeling framework is designed to predict and diagnose the complex relationships between emissions from different sources of pollutants and resulting human exposures and dose. This research program also serves to integrate and incorporate human exposure measurements, models, and methods from all aspects of EPA's research programs into a comprehensive, scientifically sound approach for evaluating human exposures. To assist the Agency in this endeavor, EPA has entered into multi-year assistance agreements with two research consortia who possess extensive experience in human exposure modeling and risk assessment. The Human Exposure and Dose Simulation University Partnership (HEASDUP) program involves five-year agreements with the Lawrence Berkeley National Laboratory (LBNL) and with the Environmental and Occupational Health Sciences Institute (EOSHI). To date, extensive collaboration among the three research groups (EPA, LBNL and EOSHI) has produced various modeling algorithms, inputs and simulation modules that can be used to estimate human exposures to particulate matter (PM) and pesticides. This symposium includes various presentations on key research components of the HEASDUP program, including applications of an integrated computer modeling platform (MENTOR) and the Stochastic Human Exposure and Dose Simulation (SHEDS) model for PM.
This abstract has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Comparisons of Pesticide Levels and Exposures in NHEXAS Arizona and Arizona-Mexico Border Populations 10/24/2000
Nishioka, M. G., M. C. Brinkman, S. M. Gordon, M. K. O'Rourke, M. D. Lebowitz, S. R. Rogan, D. J. Moschandreas, AND G. L. Robertson. Comparisons of Pesticide Levels and Exposures in NHEXAS Arizona and Arizona-Mexico Border Populations. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: The distributions of organophosphate (OP) insecticides chlorpyrifos and diazinon in exposure matrices such as indoor air, house dust, food, and water have been determined for 416 homes in the general Arizona population, and for 87 homes along the Arizona-Mexico border. The concentrations of the pesticides in these media were compared for the 50th, 75th, 90th, and 95th percentiles of the populations. The levels of diazinon were similar for the two populations, however differences were found in chlorpyrifos distributions for these two populations. In particular, the median values were higher for the border communities, but at the 90-95th percentiles, the concentrations of chlorpyrifos in exposure media were substantially higher in the general population compared to the border area. This may be related to differences in SES and/or housing characteristics. Both OPs appear together in these homes, and the sum of the two OPs by home along the border is 50% higher than would be predicted by simple addition of the individual distribution functions. Given their similar mode of action, pesticide exposures may need to be considered in terms of the sum of OPs rather than individually. Exposure estimates, and comparisons with urinary values, indicate that a significant mode of exposure is not accounted for at this time; this component may be due to a higher than anticipated vapor phase dermal penetration rate or to ingestion of TCPy in food.
The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed.
PRESENTATION Regression Models of Residential Exposure to Chlorpyrifos and Diazinon 10/24/2000
Moschandreas, D. J., S. Karuchit, Y. Kim, H. Ari, M. D. Lebowitz, M. K. O'Rourke, S. M. Gordon, AND G. L. Robertson. Regression Models of Residential Exposure to Chlorpyrifos and Diazinon. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: This study examines the ability of regression models to predict residential exposures to chlorpyrifos and diazinon, based on the information from the NHEXAS-AZ database. The robust method was used to generate "fill-in" values for samples that are below the detection limit. Such values were assigned once and were used for all analyses in the study. The dependent variables were route-specific pesticide exposures estimated via the scenario evaluation approach. Twenty-nine potential determinants of exposure, the independent variables, were identified from six questionnaires used in the study. Twelve formulation schemes that are different in terms of selection techniques and sets of independent variables used were employed. Model formulations in these schemes were done using all available subjects and then repeated using only subjects with above detection limit concentration values. Model performance was evaluated by the square of the multiple correlation coefficient, R2, and the root mean square error (RMSE). Four schemes employed the minimum-effort approach, which uses only independent variables from the questionnaires in the formulation. This approach yields models that predict up to 65 percent of the variation of the estimated exposure. The rest of the schemes employ the second approach, which added pesticide concentrations in media not included in route-specific exposure estimations to the model-formulation process. The addition improved model performance considerably. Residual analyses were performed. All selected models satisfy or nearly satisfy criteria regarding the mean, variance, and normal distribution of residuals. Logistic regression models did not have better performance when formulated based on the selected multiple regression models. Sample size was a constraining factor in the model formulation. This study shows that multiple regression models can be used to predict exposures to pesticides in residences with information obtaining from questionnaires only. The study identified several potential determinants of exposure to pesticides. No clear pattern was obtained regarding route or pesticide has better prediction models.
The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed.
PRESENTATION Characterization of Residential Exposure to Chlorpyrifos and Diazinon 10/24/2000
Moschandreas, D. J., Y. Kim, S. Karuchit, H. Ari, M. D. Lebowitz, M. K. O'Rourke, S. M. Gordon, AND G. L. Robertson. Characterization of Residential Exposure to Chlorpyrifos and Diazinon. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Exposures to chlorpyrifos and diazinon in residential microenvironment in AZ were estimated using the indirect method of exposure calculation by combining measured concentrations in multiple media with time subjects spent indoors, dietary and non-dietary items they consumed, and areas they touched using the database generated by the NHEXAS-AZ study. Four-stage probability sampling design for sample selection, robust method for treatment of censored data, sampling weight for unbiased estimates of population parameters, and deterministic models for inhalation, dietary and non-dietary ingestion, and dermal exposures were used in this study. The distribution of in-residence exposure to chlorpyrifos and diazinon appears to be log-normal or nearly log-normal. Exposures to chlorpyrifos and diazinon vary by pesticide and route as well as by various demographic characteristics of the subjects. Comparisons of exposure to pesticides were investigated among subgroups of demographic categories, including gender, age, minority status, education, family income, household dwelling type, year the dwelling was built, pesticide use, and carpeted areas in the dwellings. From the hypothesis test, a clear pattern could not be established using exposure differences between several subpopulation groups. Depending on the route, several other determinants of exposure to pesticides were identified, including gender, family income, type of house structure, minority status, pesticide use during the sampling week, year dwelling was built, and others.
The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed.
PRESENTATION Exposure to Pesticides By Medium and Route: the 90th Percentile and Related Uncertainties 10/24/2000
Moschandreas, D. J., H. Ari, S. Karuchit, Y. Kim, M. D. Lebowitz, M. K. O'Rourke, S. M. Gordon, AND G. L. Robertson. Exposure to Pesticides By Medium and Route: the 90th Percentile and Related Uncertainties. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: This study investigates distributions of exposure to chlorpyrifos and diazinon using the database generated in the state of Arizona by the National Human Exposure Assessment Survey (NHEXAS-AZ). Exposure to pesticide and associated uncertainties are estimated using probabilistic methods with the Monte Carlo simulations. The 90th percentile of inhalation, dietary ingestion, dermal and non-dietary ingestion exposure to chlorpyrifos and diazinon of the Arizona population were estimated. Questions associated with the uncertainty of exposure estimates for the two pesticides are investigated using pertinent segments of the NHEXAS-AZ study database. Probabilistic models are also used to formulate distributions of exposures to each of the two pesticides, for several sub-population groups. Parameter uncertainties associated with the 90th and other percentiles of population and sub-population groups are addressed in this study. All subjects exposed to levels above the 90th percentile of inhalation exposure value level live in dwellings with over 50 percent floor areas covered by carpets. Inhalation exposure above or below the 90th percentile value is also related to subject education. The relative uncertainty of the 90th percentile of dermal exposure is larger than corresponding uncertainties for inhalation, dietary ingestion, and non-dietary exposure.
The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed.
PRESENTATION The Influence of Human Activity Patterns on Personal PM Exposure: A Comparative Analysis of Filter-Based and Continuous Particle Measurements 10/24/2000
Rea, A. W., M. J. Zufall, R. W. Williams, C. HowardReed, AND L. S. Sheldon. The Influence of Human Activity Patterns on Personal PM Exposure: A Comparative Analysis of Filter-Based and Continuous Particle Measurements. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Particulate matter (PM) exposure data from the U.S. Environmental Protection Agency sponsored 1998 Baltimore and 1999 Fresno PM Exposure Studies were analyzed to identify important microenvironments and activities that may lead to increased particle exposure for select elderly (>65) subjects. Integrated 24-hour filter-based PM2.5 and/or PM10 mass measurements (using Personal Environmental Monitors or PEMs) included personal, indoor and outdoor residential, a central indoor site, and at a community monitoring site. A subset of the participants in each study wore passive nephelometers that continuously measured (1 min averaging time) particles ranging in size from 0.1 to ~10 um. Significant activities and locations were identified by a statistical mixed model (p<0.01) for each study population based on the measured PM2.5 or PM10 mass and time activity data. Elevated PM concentrations were associated with traveling (car or bus), commercial locations (store, office, mall, etc.), restaurants, and working. The modeled results were compared to continuous PM concentrations determined by the nephelometers while participants were in these locations. Overall, the nephelometer data agreed within 6% of the modeled PM2.5 results for the Baltimore participants and ~20% for the Fresno participants (variability was due to zero drift associated with the nephelometer). The nephelometer did not agree as well with the PM10 mass measurements, most likely because the nephelometer optimally responds to fine particles (0.3-2 um). Approximately half (54 + or - 31%; mean + or - std. dev. from both studies) of the average daily PM2.5 exposure occurred inside residences, where the participants spent an average of 83 + or - 10% of their time. These data also showed that a significant portion of PM2.5 exposure occurred in locations where participants spent only 4-13% of their time.
The information in this document has been funded wholly or in part by the United States Environmental Protection Agency through Contract #68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
PRESENTATION Approaches for Measuring Applicator Exposure in the Agricultural Health Study/Pesticide Exposure Study 10/24/2000
Thomas, K. W., L. S. Sheldon, M. S. Okino, D. P. Sandler, M. Dosemeci, AND M. R. Alavanja. Approaches for Measuring Applicator Exposure in the Agricultural Health Study/Pesticide Exposure Study. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: The Agricultural Health Study (AHS) is a prospective epidemiologic study of a large cohort of pesticide applicators and their spouses in Iowa and North Carolina. The Pesticide Exposure Study is a sub-study to evaluate exposure factors and to provide data to assess exposure classification procedures. Exposure to two applied pesticides (2,4-D and chlorpyrifos) will be measured for up to 160 applicators and their families. Applicators are selected based on application methods and uses of personal protective equipment of interest for the epidemiological study cohort. Two exposure measurement approaches are being employed: a) a combination of dermal patch, hand wipe, and personal air measurements collected during an observed handling, mixing, loading, and application (HMLA) and, b) urinary biomarker measurements from samples collected in the morning before and at two time intervals after the observed HMLA. A target goal of monitoring for 28 applicators was set for Year 1 work in Iowa; however, only 10 applicators were monitored due to scheduling delays and an early planting season. Participation information and pesticide use data are provided for Year 1 monitoring participants. Preliminary measurement results will be shown for Year 1 monitoring, including examples of dermal sample concentrations and urine concentrations for for applicators and family members. The study will continue in Year 2 in Iowa and North Carolina, with a goal of monitoring 70 applicators and repeat monitoring for 10 applicators. Current participation information is provided for Year 2 screening and recruitment to date.
This work has been funded in part by the U.S. Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names of commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Determining the Economic Value of Improved Human Exposure Data 10/24/2000
Leovic, K. W., E. Ruder, T. H. Walker, H. A. Roman, J. E. Neumann, K. D. Walker, L. S. Sheldon, AND A. Keeler. Determining the Economic Value of Improved Human Exposure Data. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: The U.S. EPA develops and revises environmental regulations and policies to protect the environment and human health. One of the key components of the regulatory process is establishing the proposed action level, which requires high quality exposure data. In many cases, exposure data for environmental contaminants are not available or data are limited in quantity and/or quality. In lieu of exposure data, EPA must make assumptions about human exposure and use models when developing regulations. The purpose of this study is to quantify the economic value of human exposure data towards improving human health protection.
Two primary economic benefits are anticipated: 1) more efficient pollutant regulation, and 2) improved human health protection. First, with both consistent and high quality information, reliance on default assumptions in developing regulations will be reduced, potentially resulting in reduced regulatory costs. More precise exposure information also allows the risk manager to determine if existing regulations have achieved intended goals. Secondly, the additional information provided by probability-based national exposure research programs could identify emerging health risks that may result in new regulations to protect health.

To quantify the value of information (VOI) for improved human exposure data, three case studies of EPA regulatory actions will be evaluated: 1) motor vehicle emissions, 2) childhood lead exposure, and 3) pesticides. Through these case studies, the VOI will be assessed, followed by a broader analysis of Agency-wide benefits. For example, estimated costs (in 1990 $) in 2000 for the Title I-VI air pollution control programs are $20 billion, and estimated benefits are $95 billion. If improved exposure data increased net benefits by only 1%, the VOI would be $750 million per year.

This work has been funded wholly by the U.S. EPA under contract to Industrial Economics, Incorporated. It has been subjected to Agency review and approved for publication.
PRESENTATION Storage Stability of Pesticides in Extract Solvents and Sampling Media 10/24/2000
Ortiz, M. M., D. E. Camann, P. W. Geno, A. Y. Yau, W. D. Ellenson, H. L. Crist, AND A. E. Bond. Storage Stability of Pesticides in Extract Solvents and Sampling Media. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Demonstrating that pesticides are stable in field media and their extracts over extended storage periods allows operational flexibility and cost efficiency. Stability of the 31 neutral pesticides and 2 acid herbicides of the Agricultural Health Study exposure pilot was evaluated for air samples, wipe samples, and their extracts.
To simulate extracts, 31 pesticides were prepared in diethyl ether/hexane (1:9) at~-0.5 ug/mL, 9 pesticides at ~0.5 mg/mL, and 2 acid herbicides in acetonitrile at both levels. The solutions were stored in vials at -12?8?C. After designated storage intervals, three replicates at each concentration were removed from the freezer and analyzed. None of the pesticides showed significant loss through 238 days of storage, except for captan and folpet at the low concentration and terbufos at the high concentration. Acid herbicide losses were 15-20% through 113 days.

To simulate air samples, cleaned polyurethane foam (PUF) and quartz filter media were spiked with ~0.5 ug each of 31 pesticides or 2 acid herbicides and stored at -12?8?C. After designated storage intervals, three replicates were removed for extraction and analysis. Most pesticides were stable through 120 days of storage. Trifluralin, phorate, dicloran, and terbufos were poorly extracted from PUF and filter. Significant losses were observed for metalaxyl by day 14 and captan and folpet by day 60. Anomalous losses of diazinon, malathion, and fonofos were seen only on day 60. Dicamba was stable through 59 days, but 2,4-D recovery remained ~65% after day 14.

To simulate wipe samples, Sof-wick sponges were wetted with isopropanol, spiked with ~1 ug of 31 pesticides and 2 acid herbicides, and stored at -12?8?C. A problem traced to the extract evaporator prevented a full evaluation. Most pesticides and both acid herbicides were stable through the 48-day storage period. Losses of trifluralin, phorate, dicloran, chlorothalonil, terbufos, captan, and folpet suggested inefficient extraction and/or storage instability.

This work was funded by the U. S. Environmental Protection Agency under contract 68-D5-0049 to ManTech Environmental and its subcontractor Southwest Research Institute. It has been subjected to Agency review and approved for publication
PRESENTATION Preliminary Findings from the NERL Research Triangle Park Particulate Matter Panel Study 10/24/2000
Williams, R. W., V. R. Highsmith, L. S. Sheldon, A. W. Rea, A. F. Vette, J. C. Suggs, K. W. Leovic, C. HowardReed, G. Saunders, A. Ejire, C. E. Rodes, J. Thornburg, AND P. A. Lawless. Preliminary Findings from the NERL Research Triangle Park Particulate Matter Panel Study. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: The U.S. Environmental Protection Agency is currently conducting the National Exposure Research Laboratory (NERL) Research Triangle Park (RTP) Particulate Matter (PM) Panel Study. This study represents a one year investigation of PM and related co-pollutants involving two distinct populations living within the RTP. A primary goal of the study is to characterize the relationships between ambient and residential PM measures to those obtained from personal exposure monitoring. Approximately 30 participants will be enrolled for personal PM2.5 exposure monitoring from potentially susceptible populations. The participants will be recruited from low socio-economic-status (SES) African-Americans and those having implanted cardiac defibrillators. Each subject will be monitored for 7 consecutive days during each of four seasonal periods (summer 2000, fall 2000, winter 2001, spring 2001). A variety of integrated and real-time residential indoor, outdoor, and ambient PM and related co-pollutant measurements will be conducted. Measures of lung function and heart rate will be obtained from each participant as a means to investigate physiological health effects of PM exposure. Data presented will include a detailed description of the peer-reviewed study design. Preliminary mass concentration data from the summer 2000 exposure monitoring period will be compared to recent EPA PM panel studies in Baltimore, MD and Fresno, CA. These earlier studies established PM2.5 personal clouds of approximately 3 ug/m3 among elderly volunteers living within retirement communities. Results from these comparative studies indicate that subject population time activity patterns, housing conditions, and other factors influence personal PM exposure measurements.
This work has been funded wholly by the United States Environmental Protection Agency under contract #68-D-99-012 to the Research Triangle Institute and assistance agreement #CR-828186-01-0 to Shaw University. It has been subjected to Agency review and approved for publication.
PRESENTATION Frequency of Mouthing Behavior in Young Children 10/24/2000
Tulve, N. S., J. C. Suggs, S. Davis, D. K. Mirick, T. R. McCurdy, AND J. Moya. Frequency of Mouthing Behavior in Young Children. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Young children, as compared to adults, are more likely to be exposed after a pesticide application due to potential hand- and object-to-mouth contacts in contaminated areas. However, relatively few studies have specifically evaluated mouthing behavior in children <60 months of age. Previously unpublished data collected by the Fred Hutchinson Cancer Research Center (FHCRC) were analyzed to assess the mouthing behavior of 86 children (43 male/43 female). Total mouthing behavior included the daily frequency of both mouth and tongue contacts with hands, other body parts, surfaces, natural objects, and toys. Eating events were excluded. Children ranged in age from 10 to 60 months. Replicate observations on different days were available for 98% of the children.
The total data set was disaggregated by gender into 5 age groups (10-20, 20-30, 30-40, 40-50, 50-60 months). Statistical analyses of the data were then undertaken to determine if significant differences existed among the age/gender subgroups in the sample. Since the data showed correlation between multiple observations for each subject, unbalanced data, and variation between subjects, a mixed effects linear model was used to test the associations between age, gender, and mouthing frequencies. Subjects were treated as random and independent, and intra-subject variability was accounted for with an autocorrelation function.

Model results indicated that there was no association between mouthing frequency and gender. However, a clear relationship was observed between mouthing frequency and age. Using a tree analysis, two distinct groups could be identified: children <24 and children >24 months of age. Children <24 months exhibited the highest frequency of mouthing behavior with 76+5 freq hr-1 (mean+ std err) (n=30 subj, 106 obs). Children >24 months exhibited the lowest frequency of mouthing behavior with 38+3 freq hr-1 (n=56 subj, 192 obs). These results suggest that children are less likely to place objects into their mouths as they age. These changes in mouthing behavior as a child ages may help in modeling total aggregate exposure to pesticides after an application event. Further statistical analyses are being performed to categorize the types of mouthing events by age, gender, and locations.

This work has been funded wholly by the United States Environmental Protection Agency under EPA Cooperative Agreement CR 816334-01 to the Fred Hutchinson Cancer Research Center. It has been subjected to Agency review and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION The Contribution of Ambient PM2.5 to Total Personal Exposures: Results from a Population Exposure Model for Philadelphia, Pa 10/24/2000
Burke, J. M., M. J. Zufall, A. H. Ozkaynak, AND J. Zidek. The Contribution of Ambient PM2.5 to Total Personal Exposures: Results from a Population Exposure Model for Philadelphia, Pa. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: The US EPA National Exposure Research Laboratory (NERL) is currently developing an integrated human exposure source-to-dose modeling system (HES2D). This modeling system will incorporate population exposure modules that use a probabilistic approach to predict population exposures to environmental pollutants, including ambient particulate matter (PM). A first-generation population exposure model for PM, called the Stochastic Human Exposure and Dose Simulation (SHEDS-PM) model, has been developed and applied to the population living in Philadelphia, PA.
SHEDS-PM estimates the population distribution of PM exposures by randomly sampling from various input distributions, including both ambient PM concentrations and emission strengths for indoor sources of PM (e.g., cigarette smoking, cooking). A steady-state mass-balance equation is used to calculate indoor PM concentrations for the home microenvironment using ambient PM concentrations and distributions of available physical factor data (e.g., air exchange, penetration, deposition). PM concentrations in non-residential microenvironments are calculated based on distributions of the effective penetration of ambient PM, which were produced using regression analysis of available measurement data for vehicles, offices, restaurants/bars, schools and stores. Additional model inputs include demographic data for the population being modeled and human activity pattern data from NERL's Consolidated Human Activity Database (CHAD). Model outputs include distributions of PM exposures in various microenvironments (indoors, in vehicles, outdoors), and the percent contribution from PM of ambient origin to total personal PM exposures in these microenvironments.

SHEDS-PM has been applied to the population of Philadelphia using spatially-interpolated ambient PM2.5 measurements and 1990 Census data for each census tract in Philadelphia. The resulting distributions of predicted PM2.5 population exposures showed significant differences in PM2.5 exposures for the population of Philadelphia that were largely due to variability in human activities since spatial differences in ambient PM2.5 measurements were not substantial. PM2.5 of ambient origin contributed significantly to total personal exposures, especially for people who spend most of their day either outdoors or indoors at home with no indoor PM2.5 source.

This abstract has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION The Use of Computer Modeling Packages to Illustrate Uncertainty in Risk Assessments: An Ease of Use and Interpretation Comparison 10/24/2000
Rigas, M. L. AND D. M. Hassenzahl. The Use of Computer Modeling Packages to Illustrate Uncertainty in Risk Assessments: An Ease of Use and Interpretation Comparison. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Consistent improvements in processor speed and computer access have substantially increased the use of computer modeling by experts and non-experts alike. Several new computer modeling packages operating under graphical operating systems (i.e. Microsoft Windows or Macintosh) make it easier for sophisticated lay individuals and policymakers without modeling backgrounds to exercise and manipulate probabilistic exposure and risk models. It is likely that individuals and communities will increasingly rely on such models as they make environmental exposure and risk decisions. We compare the speed and ease of use of three packages, Modelmaker 4.0 (Cherwell Scientific; Oxford, UK), Crystal Ball (Decisioneering; Denver, CO), and Matlab (The Mathworks; Natick, MA). The packages were used to solve a Monte Carlo exposure model designed to evaluate the risks of exposure to UDMH, a breakdown byproduct of Alar in cooked apple products, and aflatoxin, a naturally occurring contaminant in peanut butter (Kammen, DM and Hassenzahl, DM. (1999) Should we Risk It? Exploring Environmental, Health, and Technological Problem Solving. Princeton University Press; Finkel, AM (1995), Toward Less Misleading Comparisons of Uncertain Risks - the Example of Aflatoxin and Alar. Environmental Health Perspectives 103(4) 376-385). Individuals with little or no previous Monte Carlo experience were asked to manipulate the models and draw conclusions based on the results. While Matlab has numerous built-in powerful mathematical functions, the Excel interface used by Crystal Ball is familiar to many people. The low-cost and graphical interface of ModelMaker 4.0 makes this package an equally attractive option for many risk assessors.
This work has been funded wholly or in part by the United States Environmental Protection Agency and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Modeling Aggregate Chlorpyrifos Exposure and Dose to Children 10/24/2000
Zartarian, V., A. H. Ozkaynak, J. Xue, W. G. Glen, AND E. J. Furtaw Jr. Modeling Aggregate Chlorpyrifos Exposure and Dose to Children. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: To help address the aggregate exposure assessment needs of the Food Quality Protection Act, a physically-based probabilistic model (SHEDS-Pesticides, version 3) has been applied to estimate aggregate chlorpyrifos exposure and dose to children. Two age groups (0-4, 5-9 years) and 3 time periods (<1 day, 1-7 day, 8-30 days) post-indoor crack and crevice application of chlorpyrifos were considered.
Time-location-activity diaries from the National Human Activity Pattern Survey for 1092 children were randomly sampled to generate a population of simulated children. For each location-activity combination in each child's diary, model input values were sampled from probability distributions: air, dust, soil, and surface residue concentrations; meal-specific food, beverage, and drinking water residues ingested; exposure factors; uptake factors; and pharmacokinetic rate constants. These inputs were combined to yield the children's daily exposure and dose time profiles for the inhalation, dietary and non-dietary ingestion, and dermal contact exposure routes. The daily time profiles were then aggregated across all routes and pathways. A simple pharmacokinetic component was incorporated to predict real-time metabolite concentrations in the blood compartment and eliminated urine. Two-stage Monte-Carlo sampling and initial sensitivity analyses were conducted to characterize variability and uncertainty in model outputs, and to identify the relative importance of routes, pathways, and model inputs.

Population distributions for route-specific and aggregate exposure and dose estimates for various exposure scenarios are presented. Modeled estimates for concentrations in urine of 3,5,6-trichloro-2-pyridinol (TCP), a metabolite of chlorpyrifos, compare well to measured children's levels in several studies, including EPA's NHEXAS. Results indicate that dermal contact with and non-dietary ingestion of residues from a recent pesticide application can be significant contributors to exposure and dose.

This abstract has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Multiyear Real-Time Monitoring of Particles, PAH, and Black Carbon in An Occupied House 10/24/2000
Wallace, L. A., C. HowardReed, AND S. J. Emmerich. Multiyear Real-Time Monitoring of Particles, PAH, and Black Carbon in An Occupied House. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Concentrations of ultrafine, fine, and coarse particles, particle-bound polycyclic aromatic hydrocarbons (PAH), and black carbon have been measured continuously (every 1 to 5 minutes) in an occupied townhouse for 2-3 years. Also, since the summer of 1999, temperature (outdoors and at 10 indoor locations), humidity (outdoors and at five indoor locations), air exchange rates (using tracer gas decay methods at 10 indoor locations), and local (rooftop) wind speed and direction have been measured at periods ranging from every six seconds (wind velocity) to every 10 minutes. The purpose has been to document particle concentrations, seasonal variations, important indoor and outdoor relationships between house characteristics (e.g., air exchange rates), personal activities (e.g., window opening behavior) and resulting concentrations of the target pollutants. Many forms of cooking (frying, deep frying, stir-frying, sauteeing, and broiling) produced order-of-magnitude increases in the number of ultrafine and fine particles, and occasionally coarse particles as well. Cooling was by far the single most important indoor source of particles in this home containing two adult non-smokers. Ultrafine particles were produced in quantity (concentrations > 1000 particles per cc for particles with diameters between 9.8 and 10.2 nm) by gas burners and by an electric toaster oven. The two most important outdoor sources of elevated indoor concentrations of PAH and black carbon were traffic (weekday mornings only) and wood smoke (fall and winter evenings only). However, these sources were not important in terms of number of mass of particles indoors. Judging from limited outdoor measurements and the persistence of nonzero indoor concentrations when no indoor sources were operating, background outdoor concentrations of ultrafine and fine particles, particularly below 1 micrometer in diameter, produced a substantial proportion of the total number of particles indoors. A powerful, though infrequent source of PAH and black carbon indoors was barbecueing on the patio. The most important indoor source of PAH and black carbon was the use of candles, although cooking could sometimes elevate these pollutants. Coarse particles were continually produced by simple activities such as sitting, walking, and other bodily motions, suggesting resuspension of particles from carpets or clothes. Approximately a million observations of fine and coarse particle number concentrations (50 sizes from 0.3-20 micrometer) and a quarter of a million observations of ultrafine particle number concentrations (100 sizes from 10-1000 nm) have been made to date.
This abstract has been reviewed and approved by EPA. Mention of brand names is not tantamount to endorsement.
PRESENTATION Cooking-Related Particle Concentrations Measured in An Occupied Townhome in Reston, Va 10/24/2000
HowardReed, C., L. A. Wallace, AND S. J. Emmerich. Cooking-Related Particle Concentrations Measured in An Occupied Townhome in Reston, Va. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: In non-smoking households, cooking is one of the most significant sources of indoor particles. To date, there are limited data available regarding indoor particle concentrations generated by different types of cooking. To increase the knowledge base associated with particles generated by cooking, a one-year study was conducted to continuously measure particle concentrations and air change rates during cooking events by the occupants of a townhome located in Reston, VA. All cooking took place on the second level of the three-level 400 cubic meter home. A Scanning Mobility Particle Sizer (SMPS; TSI, Inc.), located on the bottom level of the house, measured ultrafine particles from 0.01 micrometers to ~ 0.5 micrometers every five minutes. An Aerodynamic Particle Sizer (APS; TSI, Inc.), located on different levels of the home during the study, measured 0.5 micrometer to 20 micrometer particles every minute. Four Climet Model 500-I optical scattering devices (Climet Instruments, Inc.) were used to measure 0.3 micrometer to > 10 micrometer particles every five minutes on each floor of the townhome as well as outdoors. To determine air change rates, a gas chromatograph with electron capture detector (GC/ECD) was used to measure the decay of sulfur hexafluoride on each level of the house. Indoor particle concentrations were measured for more than 500 cooking events during the year. Types of cooking that significantly increased indoor ultrafine particle concentrations included boiling water, baking, making popcorn, broiling, sauteeing, and deep-frying using a gas range. Broiling, deep-frying, frying, and stir-frying also elevated levels of fine particles above background. The number of particles emitted during different types of cooking events and associated deposition rates may be used to calculate particle exposures of people due to cooking.
The research described in this abstract has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Application of Semipermeable Membrane Devices to Indoor Air Sampling 10/24/2000
Robertson, G. L., J. Petty, J. Huckins, M. K. O'Rourke, S. R. Rogan, AND M. D. Lebowitz. Application of Semipermeable Membrane Devices to Indoor Air Sampling. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Semipermeable membrane devices (SPMDs) are a relatively new passive sampling technique for nonpolar organic compounds that have been extensively used for surface water sampling. A small body of literature indicates that SPMDs are also useful for air sampling. Because SPMDs have a large sample capacity and can be left in place for a long period of time they could be useful for providing an integrated measure of long term exposure to airborne organic contaminants such as pesticides, PAHs, and PCBs. The current work involved placing SPMDs in approximately 50 homes as part of a larger study. The SPMDs were exposed in the living area of the home for 30 days and returned to the laboratory for analysis for organochlorine pesticides, PAHs, and PCBs. A subset of the SPMDs was additionally analyzed for representative organophosphate and pyrethrin pesticides. Conventional (glass fiber filter and PUF cartridge, PM10 cut point) air samples were collected during a three-day period within the time the SPMDs were exposed. Representative organochlorine pesticides analyzed by both methods included p,p-DDT, p,p-DDE, trans-chlordane, and dieldrin. The following are percent detects by SPMD, percent detects by the conventional method, with n = 49 : p,p-DDT 39%, 33%; p,p-DDE 96%, 73%; trans-chlordane 98%, 78%; dieldrin 41%, 10%. Results for the subset of other pesticides, n = 11, includes diazinon 100%, 100%; chlorpyrifos 100%, 100%. These preliminary results show that SPMDs are highly effective at collecting integrated samples of airborne pesticides. Additional results comparing amounts found will be presented.
The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed.

PRESENTATION Fixed-Site Air and Biomarker Measurements of Vocs in a Non-Occupationally Exposed Population Along the Arizona-Mexico Border 10/24/2000
Gordon, S. M., M. C. Brinkman, P. J. Callahan, M. D. Lebowitz, M. K. O'Rourke, S. R. Rogan, D. L. Ashley, L. Needham, J. L. Pirkle, D. J. Moschandreas, AND G. L. Robertson. Fixed-Site Air and Biomarker Measurements of Vocs in a Non-Occupationally Exposed Population Along the Arizona-Mexico Border. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: The goals of the NHEXAS-Border Study are to obtain environmental exposure and biomarker data for a representative population residing along the Arizona-Mexico border, and compare the distributions to similar distributions previously obtained for the state of Arizona (NHEXAS-Arizona) and to reference ranges of biomarkers for the general U.S. population (provided by NHANES III, the Third National Health and Nutrition Examination Survey). Residential environmental measurements were made of multiple pollutants (pesticides, metals, VOCs, PAHs) in a variety of media (air, soil, house dust, food, and drinking water) at a total of 86 homes along the Arizona-Mexico border; biomarker measurements were made in blood and urine.
For the fixed-site air VOCs collected using passive samplers, only 12.5% of the measurements of outdoor samples and 17.1% of the indoor samples were above the method detection limit (13 target compounds). Samples taken using actively-pumped collectors yielded detectable rates of 28.3% for outdoor samples and 38.7% for indoor samples (38 target compounds). For the 12 VOCs measured in blood, the percentage of measurements above the detection limit was 52.9%. About 10% of the blood VOC levels were significantly elevated for 1,4-dichlorobenzene relative to the NHANES III reference, and were above the 90th percentile. By contrast, 1,1,1-trichloroethane and trichloroethene were substantially lower than the NHANES III reference. The fixed-site indoor air concentrations for 1,4-dichlorobenzene were also very high at the 90th percentile compared with values reported in previous monitoring studies. In all homes yielding 1,4-dichlorobenzene air concentrations above the 90th percentile, the concentration of the chemical in the blood of the primary respondents was also greater than the 90th percentile. In some cases, this was attributed to the use of household consumer products, such as room deodorizers or mothballs, in these homes.

The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed.
PRESENTATION Evaluation of Analytical Methods for Determining Pesticides in Foods 10/24/2000
Chuang, J. C., J. S. Chang, L. E. Bowman, J. M. Van Emon, AND A. W. Reed. Evaluation of Analytical Methods for Determining Pesticides in Foods. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Children can be exposed to pesticides by inhaling contaminated air, ingesting tainted food or non-dietary substances, or absorbing them through the skin from contaminated media. Earlier pilot-scale exposure studies suggest that dietary ingestion is an important pathway for children's exposure to some pesticides. Determinations of pesticides in food are often complicated by the presence of fats, and therefore require multiple cleanup steps before analysis. Cost-effective analytical methods are needed for conducting large-scale exposure studies.
In this presentation, we discuss the investigation of several extraction methods and clean-up procedures for determining target pesticides in baby foods. The extraction techniques examined were supercritical fluid extraction (SFE) and accelerated solvent extraction (ASE). The clean-up procedures evaluated were C18 solid phase extraction (SPE), basic alumina SPE, ENVI-Carb SPE, and tandem SPE column (ENVI-Carb-florisil, ENVI-Carb-amino). The detection techniques used were enzyme-linked immunosorbent assay (ELISA) and gas chromatography/mass spectrometry (GC/MS).

The SFE-GC/MS procedures evaluated did not provide quantitative recoveries (<50%) of the spiked pesticides in fatty baby foods. Using SFE-GC/MS, recoveries of target pesticides were greater than 80% in dried baby food, but 10-60% of the spiked pesticides were lost during the freeze-drying process. The ASE-ELISA method provided a quantitative determination of atrazine in both non-fat and fatty baby food. Several spike recovery tests were carried out to determine target pesticides in baby foods using ASE-GC/MS. These tests resulted in an analytical method for determining target pesticides in baby foods. The method consists of extracting baby food with acetonitrile (ACN) at 80 degrees C under 2000 psi pressure, fractionating the ACN extract with ENVI-Carb SPE, and analyzing the collected fraction using GC/MS. Selected sample extracts were analyzed by ELISA and good agreement was obtained between the ELISA and GC/MS results. Duplicate diet samples from the Total Dietary Study were prepared with the above method and analyzed for four target pesticides: malathion, chlorpyrifos, P,P -DDE, and P,P -DDT. The concentrations of the target pesticides ranged from <0.3 to 110 ppb.

This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade name or commercial products has not constituted endorsement or recommendation for use.
PRESENTATION Improving the Scientific Community's Ability to Characterize Human Exposures in Low Ses Areas: Participant Recruitment and Retention 10/24/2000
Leovic, K. W., A. Ejire, R. W. Williams, V. R. Highsmith, AND L. S. Sheldon. Improving the Scientific Community's Ability to Characterize Human Exposures in Low Ses Areas: Participant Recruitment and Retention. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: EPA's environmental justice program is charged with ensuring that no segment of the population, regardless of race, color, national origin, or income, suffers disproportionately from adverse human health or environmental effects and that all people live in clean, healthy, and sustainable communities. Some studies have indicated that minority and low socioeconomic status (SES) populations have higher incidents of disease and death. Human exposure data is needed for low SES populations to determine if they are disproportionately exposed to environmental pollutants. However, limited information is available on recruitment and retention techniques for low SES populations.
During the summer of 2000, EPA's National Exposure Research Laboratory will begin a 12 month Particulate Matter (PM) Panel Study in Raleigh, NC. A primary goal of the study is to compare PM levels measured at the ambient and residential level with those from personal exposure monitoring. The study will include approximately 15 participants representing low SES African-Americans.

EPA is collaborating with Shaw University, a historically black university, to promote outreach and education on human exposure in the local community. We are investigating different techniques for enhanced participant recruitment and retention for human exposure studies conducted in low SES communities. The techniques that will be evaluated and reported on include: working with local community leaders to gain support; conducting outreach through community churches and physicians; gaining support from community groups; and enlisting the support of university employees and residents of local housing projects. We will also evaluate the success of outreach through various media. The results will provide the scientific community with improved information, techniques, and tools for conducting human exposure research in low SES communities.

This work has been funded wholly by the U.S. EPA under assistance agreement #CR-828186-01-0 to Shaw University. It has been subjected to Agency review and approved for publication.
PRESENTATION Assessment of Young Children's Potential Pesticide Exposure Following a Residential Pesticide Application. Part II Use of the Macroactivity Approach 10/24/2000
Tulve, N. S., P. Hore, E. A. CohenHubal, N. G. Freeman, P. J. Lioy, AND L. S. Sheldon. Assessment of Young Children's Potential Pesticide Exposure Following a Residential Pesticide Application. Part II Use of the Macroactivity Approach. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Young children may be more susceptible to pesticides because they are undergoing rapid physiological and behavioral development. In addition, young children, as compared to adults, are more likely to engage in activities (i.e., playing, sitting on the floor) in which they may come into direct contact with contaminated surfaces. As a result, children may be more exposed to pesticides through normal daily activities after a residential pesticide application within the home.
One method being evaluated to assess children's exposure to pesticides is the macroactivity approach. In this approach, a child's exposures to chemicals are estimated for each microenvironment where a child spends time and each macroactivity that the child conducts within that specific microenvironment. The aggregate exposure is then modeled using empirically-derived transfer coefficients specific to each microenvironment/macroactivity combination.

The Children's Post-Application Pesticide Pilot Study is a collaborative effort between the EPA and the Environmental and Occupational Health Sciences Institute (EOHSI) in New Jersey. Nine families with young children (< 5 years old) were recruited to participate in the study. Four-hour videotape segments, time-activity diaries and questionnaires, dermal wipes, and transferable residue loadings were collected during the study. Specific macroactivity and microenvironment combinations for these children were determined from the videotape segments and the time-activity diaries and questionnaires. Transferable residue loadings from the surfaces on which the children spent the majority of their time were measured using a surface sampler (i.e., modified Edwards-Lioy press sampler, Lioy-Weisel-Wainman quantitative surface sampler, or alcohol wipes). Dermal wipe concentrations, including hands and knees, were also determined. Transferable residues and dermal wipe measurements were used to calculate transfer coefficients. Transfer coefficients were found to be variable and dependent on both the activity level of the child and the contacted surfaces. These data were used to evaluate the feasibility of using the macroactivity approach to assess children's exposure.

This work has been funded in part by the United States Environmental Protection Agency under an EPA Technical Services Contract (Contract No. 0D-5227-NAEX) to the Environmental and Occupational Health Sciences Institute. It has been subjected to Agency review and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Modeling of Chlorpyrifos Exposure, Dose, and Biomarker Using NHEXAS Minnesota Children's Data 10/24/2000
Furtaw Jr., E. J., M. S. Okino, J. J. Quackenboss, A. Roy, AND P. J. Lioy. Modeling of Chlorpyrifos Exposure, Dose, and Biomarker Using NHEXAS Minnesota Children's Data. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Data from the National Human Exposure Assessment Survey (NHEXAS) are now becoming available. For the organophosphorus insecticide chlorpyrifos, available data for NHEXAS Minnesota children include concentrations in air, food, beverages, water, house dust (transferable surface residues), soil, and hand rinses; and 3,5,6-trichloro-2-pyridinol (TCPy), a chlorpyrifos metabolite, in urine. To evaluate these data, we used the environmental measurements as inputs to a dynamic model of chlorpyrifos exposure and human pharmacokinetics. The model simulated the urinary TCPy concentration. Exposure factors were taken from EPA's Office of Pesticide Programs' Draft Standard Operating Procedures for Residential Exposure Assessments and from EPA's Exposure Factors Handbook. Non-dietary ingestion from hand-to-mouth activity, and dermal absorption, collectively accounted for over 84% of the modeled absorbed chlorpyrifos dose. Measured urinary TCPy concentrations exceeded modeled concentrations by a factor of about 6. Possible explanations for this disparity include: additional unmeasured exposure to chlorpyrifos occurred outside the home; actual exposure concentrations were different than those measured due to heterogeneity of residues; exposure factors are missing or incorrect; the pharmacokinetic model (which was based on adult male data) is inappropriate for children; and additional exposure to TCPy itself (which was not analyzed in environmental samples) may have occurred. Of these, the last explanation is supported by other research which has shown that TCPy occurs in agricultural products, and even more so in prepared foods, due to environmental degradation of chlorpyrifos. This possible explanation shows the importance of carefully selecting and matching environmental and biomarker measurements in exposure studies. When the chosen biomarker is a metabolite, consideration must be given to measuring the metabolite as well as the parent compound in environmental samples.

The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed.

PRESENTATION Pesticides in Dust Samples from Homes and Schools in Yuma, Arizona 10/24/2000
Hern, S. C., G. L. Robertson, R. Hart, B. A. Schumacher, AND E. Paz. Pesticides in Dust Samples from Homes and Schools in Yuma, Arizona. Presented at International Society of Exposure Analysis, Monterey Pennisula, CA, October 24-27, 2000.
Abstract: A pilot study was conducted in Yuma, Arizona to investigate children's exposure to pesticides as detected in urine and dust samples. The principle hypothesis of the study is that pesticide levels in young children vary with the distance children live or attend school from agricultural fields. Dust samples were collected from 6 schools (14 samples) and from 151 homes (156 samples) of kindergarten and first grade children. The dust samples were tested for organophosphate pesticides and other pesticides which were used in the study area (43 pesticides). Urine samples were collected from the 152 participating children and also from their siblings between the ages of 3 to 10 years old. The urine samples of the 152 participating children were analyzed using an alkyl phosphate metabolite screen to detect exposure to organophosphorus (OP) pesticides. The urine samples of the siblings will be tested later based on the levels found in urine samples of the participating child in the household. In addition, analyses for individual pesticides may be done later if necessary. The pesticide exposure surrogates of urine and dust will be compared to distance from agricultural fields using both physical measurements and GIS technology. This presentation is restricted to the results of the dust sample analysis.
Of the 43 pesticides analyzed for in the dust samples, 18 were detected in the samples from schools while 33 were detected in the home samples. The seven most frequently detected pesticides were identical for both homes and schools; however, the rank order of the pesticides varied. It is interesting to note the high occurrence of orthophosphate compounds in schools as compared to the high incidence of pyrethroids in homes. The seven most frequently detected pesticides with the percent of detects in parenthesis for homes (H) followed by schools (S) are: trans-permethrin (92% H, 28%S), cis-permethrin (88% H, 28%S), chlorpyrifos (81%H, 86%S), diazinon (67% H, 95% S), propoxur (66% H, 52% S), o-phenylphenol (60% H, 90% S), and cypermethrin (43% H, 48% S).

The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Study to Identify Important Parameters for Characterizing Pesticide Residue Transfer Efficiencies 10/24/2000
CohenHubal, E. A., L. S. Sheldon, AND J. C. Suggs. Study to Identify Important Parameters for Characterizing Pesticide Residue Transfer Efficiencies. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and non-dietary ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study to identify the important parameters for characterizing these transfers was conducted.
In this study, parameters that affect residue transfer from surface-to-skin, skin-to-other objects, skin-to-mouth, and object-to-mouth, were evaluated using a fluorescent tracer as a surrogate for pesticide residues. A fluorescent tracer was applied as a residue at levels typical of residential pesticide applications to surfaces of interest. Controlled transfer experiments were conducted by varying contact parameters with each trial. The mass of a tracer transferred was measured and the contact surface area estimated using video imaging techniques. In addition, laboratory evaluations were conducted to relate transfer of a tracer to transfer of pesticides.

Parameters evaluated included: surface type, surface loading, contact motion, pressure, duration, and skin condition. Both transfers onto, and off of, the hand were measured. To efficiently identify parameter changes resulting in significant effects, the Youden ruggedness test was used to select the combination of parameters varied in each contact trial. In this way, more than one parameter could be varied at a time and the number of trials required was minimized.

Results of this study showed that surface type and skin condition are among the important parameters for characterizing residue transfers. Data from this study will reduce uncertainty associated with estimating dermal and non-dietary ingestion exposure. This data will also determine what additional residue transfer data should be collected and what type of microactivity data are needed to estimate dermal and non-dietary ingestion exposure. Finally, these data are required as inputs to the residential pesticide exposure models currently under development.

This work has been funded wholly or in part by the United States Environmental Protection Agency under contract no. 68-D-99-011 to Battelle. It has been subjected to Agency review and approved for publication.
PRESENTATION Field Comparisons of Dual Smps-Aps Systems to Measure Indoor-Outdoor Particle Size Distributions 10/24/2000
Vette, A. F., T. M. Peters, AND L. S. Sheldon. Field Comparisons of Dual Smps-Aps Systems to Measure Indoor-Outdoor Particle Size Distributions. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Simultaneous measurements of particle size distributions across multiple locations can provide critical information to accurately assess human exposure to particles. These data are very useful to describe indoor-outdoor particle relationships, outdoor particle penetration through a building shell and even spatial variations in particle size distribution across distances of several kilometers. To simultaneously measure particle size distributions at different locations, methodologies with demonstrated comparability are required to ensure data quality prior to field deployment. In this study, we compared two Scanning Mobility Particle Sizers (SMPS) and two Aerosol Particle Sizers (APS). The SMPS measures particles from 0.01 - 0.6 ?m and the APS measures particles from 0.7 ?m up to 10 ?m when using a PM10 inlet. In this study we examined size distributions from 0.01 - 2.5 ?m. Laboratory and field audits were conducted using an aerosol generator to produce a polydisperse aerosol of a sodium chloride solution and a monodisperse aerosol of polystyrene latex (PSL) spheres with known particle size. Instrument audits consistently showed agreement within 15%, on average, across the measured particle size range (0.01 - 2.5 ?m). Field comparisons were conducted indoors and outdoors of a seldom occupied, but furnished residence. The purpose of the field comparisons was to determine the utility of using two individual SMPS-APS systems to measure indoor-outdoor particle size distributions. In addition, one of the systems located indoors was used to alternately sample indoor and outdoor air through a controlled ball-valve switching manifold. This enabled a simultaneous comparison of a common aerosol measured by the two systems. The results from the field study showed poor agreement between the two SMPS-APS systems and point to the need for improvements in the audit system to produce aerosol concentrations in the range of those encountered in the field.
This work has been funded in part by the United States Environmental Protection Agency under Contract # 68-D5-0040 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION The Contribution of Particle Resuspension to Indoor and Personal Air Concentrations 10/24/2000
Sheldon, L. S., A. W. Rea, A. F. Vette, C. HowardReed, R. W. Williams, V. R. Highsmith, C. E. Rodes, AND P. A. Lawless. The Contribution of Particle Resuspension to Indoor and Personal Air Concentrations. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: An association has been demonstrated between ambient PM concentrations and human morbidity/mortality. However, little is known regarding the most important sources of PM exposure, inter- and intrapersonal variability in exposure, and the relationship between personal exposure and exposure estimates based on field site measurements. NERL is conducting several longitudinal Panel Studies to address these uncertainties and to evaluate the important determinates of PM exposure. As part of this effort, research is underway to evaluate the contributions to personal exposure from indoor sources and resuspended ambient particles. This paper focuses on the impacts of particle resuspension.
Panel study monitoring included personal exposure measurements of PM 2.5 mass. Both PM 2.5 and PM 10 mass measurements were also taken at ambient, outdoor, and indoor locations. Nephelometers (MIE, Inc. personalDataRam) were used to collect real-time PM 2.5 data concurrently with personal and indoor samples. Nephelometer data were downloaded each day and used to query participants about those activities that were responsible for elevated PM concentrations. Although the nephelometers did not provide accurate mass measurements, this approach provided a valuable qualitative measure of personal and indoor sources of PM. Real-time particle counts in the fine and ultrafine size range were measured both indoors and outdoors for selected microenvironments using SMPS, LASX, and APS instruments. Information on housing characteristics and activities were also collected.

Combining results from the two real-time measurement techniques provided valuable information on particle resuspension. The nephelometer and time activity data were used to determine the relative contribution of particle resuspension on personal and indoor air concentrations. The SMPS, LSX, and APS instruments were used to evaluate the size distribution of resuspended particles. Results suggest that a substantial portion of the PM in both personal and indoor air can result from particle resuspension. In addition, resuspension results in predominately coarse mode particles. Additional work is underway to identify the nature of the particles associated with resuspension.

This work has been funded wholly by the United States Environmental Protection Agency under contract #68-D-99-012 to the Research Triangle Institute. It has been subjected to Agency review and approved for publication.
PRESENTATION Use of PBPK Models for Assessing Absorbed Dose and Che Inhibition from Aggregate Exposure of Infants and Children to Organophosphorus Insecticides 10/24/2000
Blancato, J. N., J. B. Knaak, F. W. Power, AND C. C. Dary. Use of PBPK Models for Assessing Absorbed Dose and Che Inhibition from Aggregate Exposure of Infants and Children to Organophosphorus Insecticides. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: A physiological pharmacokinetic (PBPK) modeling framework has been established to assess cumulative risk of dose and injury of infants and children to organophosphorus (OP) insecticides from aggregate sources and routes. Exposure inputs were drawn from all reasonable sources, primarily food and drinking water, inhaled air, and from dermal absorption of transferred surface residues. Michaelis-Menten kinetics were used to describe hydrolysis and activation of P=S containing OP insecticides to their corresponding oxons. Biomolecular rate constants were used to describe cholinesterase inhibition, a typical biomarker for these compounds. The disposition of products of activation and metabolism were traced in tissues, organs, fluid compartments and excreta. Mass balance summaries were generated to compare routes of exposure and sources of OP contamination. The assumption of "reasonable certainty of no harm" as expressed under the Food Quality Protection Act (FQPA) was examined based on the dynamic processing of modeling data.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development, funded this research and approved this abstract as a basis for an oral presentation. The actual presentation has not been peer reviewed by the EPA.
PRESENTATION Continuous Black Carbon Measurements Indoors and Outdoors at An Occupied House for One Year 10/24/2000
LaRosa, L., C. HowardReed, AND L. A. Wallace. Continuous Black Carbon Measurements Indoors and Outdoors at An Occupied House for One Year. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Black carbon is one of the components of particulate matter, and is of importance because the only known source of aerosol black carbon in the atmosphere is the combustion of carbonaceous fuels (Hansen, 1997). Polyaromatic hydrocarbons (PAH) formed in the combustion process are generally associated with black carbon. The health effects of black carbon and associated PAHs may thus include both carcinogenicity and short-term effects associated with fine particle inhalation (e.g., decreased heart rate variability). The purposes of this study were 1) to record indoor and outdoor concentrations of black carbon every five minutes at an occupied residence over a one-year period; 2) to identify outdoor and indoor sources black carbon; and 3) to determine indoor-outdoor relationships including penetration factors and deposition rates. The residence was a three-story townhouse in a Virginia suburban location 25 miles from Washington, DC with two nonsmoking adult residents. A 10-lane toll road and airport expressway was 1.5 miles distant from the residence. Two Aethalometers (Magee Scientific Company, Berkeley, California) were used to measure simultaneous indoor and outdoor black carbon concentrations every five minutes from May, 1998 to May, 1999. After correction for an observed effect of cumulative optical depth on the Aethalometer readings, the precision of the two Aethalometers was approximately 10%. Arithmetic means (standard deviations) were 741 (611) nanograms per cubic meter outdoors and 461 (3194) nanograms per cubic meter indoors (N = 89, 771 and 94,361, respectively). During period with known indoor sources (N = 7,748 cases), the indoor arithmetic mean concentration was 1007 nanograms per cubic meter, compared to 412 nanograms per cubic meter during 86,613 cases without indoor sources. Geometric means were 573 nanograms per cubic meter outdoors and 319 nanograms per cubic meter indoors. Geometric standard deviations were 2.08 outdoors and 2.18 indoors. Peak outdoor concentrations were observed throughout the year in the 6-9 AM period, indicative of vehicular traffic. In the fall and winter months, peak outdoor concentrations were observed in the 6PM-midnight period, mostly on weekends, indicative of residential wood burning. Indoor black carbon concentrations followed the outdoor pattern, except for period when an indoor source was operating. A major source of personal exposure was found to be a Citronella which, when used as directed (within 3 feet of the person), elevated black carbon concentrations by a factor of 40-100. Analyses of Variance (ANOVA) were conducted to identify indoor and outdoor concentration patterns, and identify source. The two major indoor sources were cooking and burning candles. Linear regression analyses were conducted on the logarithms of the corrected concentrations with the following result (N=80, 760 cases; Adj. R squared = 52%):
Ln (Indoor BC) = 0.997 (0.016) + 0.745 (0.002 Ln (Outdoor BC).

This abstract has been approved by EPA. Mention of brand names is not to be construed as endorsement.
PRESENTATION Study to Test the Feasibility of Using the Macroactivity Approach to Assess Dermal Exposure 12/03/2000
CohenHubal, E. A., L. S. Sheldon, G. G. Akland, D. Whitaker, AND J. H. Raymer. Study to Test the Feasibility of Using the Macroactivity Approach to Assess Dermal Exposure. Presented at Society for Risk Analysis 2000 Annual Meeting, Arlington, VA, December 3-6, 2000.
Abstract: In the macroactivity approach, dermal exposure is estimated using empirically-derived transfer coefficients to aggregate the mass transfer associated with a series of contacts with a contaminated medium. The macroactivity approach affords the possibility of developing screening level exposure assessments in a shorter time frame and with fewer resources than would be required for the microactivity approach (in which dermal exposure is explicitly modeled as a series of discrete transfers resulting from each contact with a contaminated medium). However, the macroactivity approach was developed to assess occupational exposure in an agricultural setting where workers are engaged in similar activities and are exposed to relatively homogeneous environmental concentrations of pesticides. The macroactivity approach will only be useful for assessing dermal exposure in a residential setting if exposure can be adequately quantified by lumping children's activities into a relatively small number of macroactivities.
To assess the feasibility of using the macroactivity approach for assessing children's exposure to pesticides, a screening-level study was conducted with young children in a daycare center where a known pesticide application had occurred. Four or five children from each of two different age groups were monitored for short time periods while involved in selected macroactivities (e.g., storytime, playtime indoors). To measure dermal loading or exposure, the children were clothed in full-body dosimeters. To measure the pesticide concentration in the exposure medium, transferable residues were sampled in the areas where the children spent time during each monitoring event. In addition, videotaping was conducted to verify the children's activity levels and location during exposure monitoring. The dermal loading and transferable residue measurements were then used to calculate dermal transfer coefficients for each monitoring event. The results of this study demonstrate the variability of dermal loading (and associated transfer coefficients) for children of a given age group performing varying macroactivities. In addition, these data will be used to evaluate the default assumptions currently used in USEPA's Office of Pesticide Programs to assess children's residential exposure to pesticides.

This work has been funded wholly or in part by the United States Environmental Protection Agency under contract no. 68-D-99-012 to Research Triangle Institute. It has been subjected to Agency review and approved for publication.
PRESENTATION Controlled, Short-Term Dermal and Inhalation Exposure to Chloroform 10/24/2000
Gordon, S. M., D. Kenny, P. J. Callahan, M. C. Brinkman, L. A. Wallace, AND D. L. Ashley. Controlled, Short-Term Dermal and Inhalation Exposure to Chloroform. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Studies were conducted to determine the uptake by humans of chloroform as a result of controlled short-term dermal and inhalation exposures. The approach used continuous real-time breath analysis to determine exhaled-breath profiles and evaluate chloroform kinetics in the human body. In the first study, real-time breath analysis was used to measure dermal absorption of chloroform while showering. Six subjects (3 male, 3 female) showered in water containing chloroform (at ~ 70-90 ug/L) at two temperatures (36 C and 42 C) for 30 min. Water temperature had a powerful effect on dermal absorption; the mean amount of chloroform exhaled varied from 0.4 plus/minus 0.3 ug at 36 C to 2.6 plus/minus 1.1 ug at 42 C. This finding, which will need to be incorporated into existing and future models of dermal absorption, likely results from increased blood flow to the skin at the higher temperatures. Uptake and elimination residence times (tau uptake = 10.3 plus/minus 3.1 min; tau decay = 7.0 plus/minus 0.8 min) were similar to those determined in an earlier investigation (Gordon et al., 1998). In the second study, four of the original six subjects were exposed on five separate occasions (one subject participated twice) to 90-100 ppb chloroform-d for 2 hours, followed by exposure to clean air for 20-30 min. Exhaled breath was continuously sampled and analyzed with the real-time breath technology; blood samples were simultaneously collected from 3 of the subjects (6 samples during exposure; 6 samples post-exposure). The uptake and decay of chloroform in the blood was estimated by fitting the exposure and post-exposure breath and blood data to a multi-compartmental model that estimated residence times. The measurements also provided information on the chloroform blood:breath concentration ratio and the fraction of breath chloroform exhaled unchanged at equilibrium (~0.2).

This abstract has been reviewed in accordance with U.S. Environmental Protection Agency's peer and administrative review policies and approved for publication.
PRESENTATION Evaluation of Whole Body Dosimeters for Measuring Dermal Exposures 10/24/2000
Akland, G. G., J. H. Raymer, Y. Hu, E. D. Pellizzari, D. Whitaker, J. B. Beach, B. A. Schumacher, AND E. A. CohenHubal. Evaluation of Whole Body Dosimeters for Measuring Dermal Exposures. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Demographic Characteristics of the NHEXAS-Arizona Border Study Population 10/24/2000
O'Rourke, M. K., M. D. Lebowitz, S. M. Gordon, M. G. Nishioka, D. J. Moschandreas, AND G. L. Robertson. Demographic Characteristics of the NHEXAS-Arizona Border Study Population. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: The NHEXAS-Arizona Border Study employed a population based probability design to recruit a representative cohort residing within 40 Km of the US-Mexico Border in Arizona. As an extension of the NHEXAS Arizona statewide survey, the border study was designed to determine the distributions of total human exposure to selected metals, pesticides, volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs) in the US-Mexico Border subpopulation. Preliminary analyses indicate that 89% of households contacted agreed to participate in the study. Intensive environmental sampling (N=87 HH) was conducted between September 1997 and October 1998. A single household resident provided biological (blood and urine) and diet samples; time activity and baseline exposure data were requested of all household residents. Baseline exposure data (questionnaires) were also collected in 137 additional households. Approximately 76% of the individuals recruited were Hispanic, 48% were male, 21% were less than 16 years, and 17% were greater than 65 years of age. 67% of the population were bilingual, and 44% preferred speaking and reading Spanish to English. The median per-capita income (median HH income/number of residents) was $6,250 (min. = $1000, max. =$41,250) and demonstrated strong regional variation. 65% of the housing stock was built prior to 1979 and 69% use evaporative (swamp) coolers to cool their homes. Age, gender, ethnicity and per-capita income characteristics of the study population are reasonably well matched (p< .05) with comparable 1990 Census data at the county, tract and place (CDP) levels of census geography. Age and gender characteristics approximate 1997 and 1998 Arizona State demographic projections for counties. The NHEXAS-Arizona statewide survey and NHEXAS-Arizona Border Study afford a unique opportunity to investigate human exposure to environmental toxins in one of the fastest growing states in the nation.
The U.S. EPA Office of Research and Development funded this research. The abstract was reviewed and approved. The presentation has not been reviewed. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Assessment of Young Children's Potential Pesticide Exposure Following a Residential Pesticide Application Part I. Study Design: Exposure of Children and Toys 10/24/2000
Hore, P., N. G. Freeman, N. S. Tulve, E. A. CohenHubal, L. S. Sheldon, AND P. J. Lioy. Assessment of Young Children's Potential Pesticide Exposure Following a Residential Pesticide Application Part I. Study Design: Exposure of Children and Toys. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: Semi-volatile pesticides such as chlorpyrifos can be dynamic in nature; once applied, they can migrate spatially and concentrations can build-up in and on objects and surfaces. Such pesticides are frequently used in U.S. households. Children within these homes may be exposed to these pesticides via multiple pathways. The Children's Post Pesticide Application Exposure Study (CPPAES) is being conducted by the Environmental and Occupational Health Sciences Institute (EOHSI) in New Jersey to look at the distribution of chlorpyrifos within a home environment following a crack-and-crevice application to assess the amount of pesticide that a child may come into contact with. For this study, 10 homes with a 2-5 year old child that routinely apply pesticides have been selected. To each home a chlorpyrifos application is made by a licensed applicator. Measurements of chlorpyrifos residues are then made from the indoor air for a two-week sampling period. Smooth, cloth indicator toys that are placed within the home following the application are collected sequentially because toys can act as potential sinks within the home and are accessible to the children. Direct handrinse or handwipe samples are collected from the children on each sampling day and records are kept of the child's daily activities through time activity diaries and questionnaires. Urine samples are collected from the children each day and are analyzed for the chlorpyrifos metabolite. Preliminary results have found that chlorpyrifos is present in the indoor environment throughout the sampling period. Levels in the air ranged from 72.7 to 194.8 ng/m3 reaching peak levels between days 1 and 2. Levels in the toys ranged from 328.5 to 1091.8 ng/toy. Handrinse levels ranged from 0.56 to 1.39 ng/cm2. This study will help us estimate the potential for pesticide exposure for a child in a home environment post-application and to link environmental concentrations of chlorpyrifos to a child's actual internal dose.
This work has been funded in part by the United States Environmental Protection Agency under an EPA Technical Services Contract (Contract No. 0D-5227-NAEX) to the Environmental and Occupational Health Sciences Institute. It has been subjected to Agency review and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Chemical and Physical Characteristics of Outdoor, Indoor, and Personal Particulate Air Samples Collected in and Around a Retirement Facility 09/12/2000
Conner, T. L., G. A. Norris, R. W. Williams, AND M. S. Landis. Chemical and Physical Characteristics of Outdoor, Indoor, and Personal Particulate Air Samples Collected in and Around a Retirement Facility. Presented at EPA/AWMA International Symposium on the Measurement of Toxic and Related Air Pollutants, Research Triangle Park, NC, September 12-14, 2000.
Abstract: Residential, personal, indoor, and outdoor sampling of particulate matter was conducted at a retirement center in the Towson area of northern Baltimore County in 1998. Concurrent sampling was conducted at a central community site. Computer-controlled scanning electron microscopy with individual-particle x-ray analysis (CCSEM) was used to measure the chemical and physical characteristics of non-carbonaceous particles collected at the indoor, outdoor and community sampling locations. Indoor residential and personal samples were examined using scanning electron microscopy with individual-particle x-ray analysis (SEM/EDX) in the manual mode.
The CCSEM results show that the relative abundances of particle classes identified at the outdoor and community locations differ from each other and from the indoor location. These results indicate that community-based sampling may not yield samples which, on an individual particle basis, are representative of the particles found indoors. Particle images acquired during the computer-controlled analyses played a key role in the identification of certain particle types, though review of particle images was time-intensive.

Manual SEM/EDX examination of personal samples suggest personal care products and hobbies or other activities (in addition to cooking and cleaning) as possible sources of particle exposure. Quantitative differences among selected personal and residential samples were observed. We conclude that CCSEM and manual SEM/EDX can contribute to the understanding of the sources of particulate matter in different micro-environments.

This work has been funded wholly or in part by the United States Environmental Protection Agency under contract #68-D5-0040 to the Research Triangle Institute and under contract #68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.
PRESENTATION Chemical and Physical Characterization of Indoor, Outdoor, and Personal Samples Collected in and Around a Retirement Facility 09/12/2000
Conner, T. L., G. A. Norris, M. S. Landis, AND R. W. Williams. Chemical and Physical Characterization of Indoor, Outdoor, and Personal Samples Collected in and Around a Retirement Facility. Presented at EPA/AWMA International Symposium on the Measurement of Toxic and Related Air Pollutants, Research Triangle Park, NC, September 12-14, 2000.
Abstract: Residential, personal, indoor, and outdoor sampling of particulate matter was conducted at a retirement center in the Towson area of northern Baltimore County in 1998. Concurrent sampling was conducted at a central community site. Computer-controlled scanning electron microscopy with individual-particle x-ray analysis (CCSEM) was used to measure the chemical and physical characteristics of non-carbonaceous particles collected at the indoor, outdoor and community sampling locations. Indoor residential and personal samples were examined using scanning electron microscopy with individual-particle x-ray analysis (SEM/EDX) in the manual mode.
The CCSEM results show that the relative abundances of particle classes identified at the outdoor and community locations differ from each other and from the indoor location. These results indicate that community-based sampling may not yield samples which, on an individual particle basis, are representative of the particles found indoors. Particle images acquired during the computer-controlled analyses played a key role in the identification of certain particle types, though review of particle images was time-intensive.

Manual SEM/EDX examination of personal samples suggest personal care products and hobbies or other activities (in addition to cooking and cleaning) as possible sources of particle exposure. Quantitative differences among selected personal and residential samples were observed. We conclude that CCSEM and manual SEM/EDX can contribute to the understanding of the sources of particulate matter in different micro-environments.

This work has been funded wholly or in part by the United States Environmental Protection Agency under contract #68-D5-0040 to the Research Triangle Institute and under contract #68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.
PRESENTATION Transformation and Transport of Semi-Volatile Organic Compounds from Soil: Measuring Dicarboximides in a Chamber 11/05/2000
Vallero, D. A. Transformation and Transport of Semi-Volatile Organic Compounds from Soil: Measuring Dicarboximides in a Chamber. Presented at American Institute of Hydrology International Conference 2000, Research Triangle Park, NC, November 5-8, 2000.
Abstract: A laboratory chamber was used to determine transport of a suspected anti-androgenic dicarboximide fungicide, vinclozolin (3,5-dichlorophenyl)-5-methyl-5-vinyl-oxzoli-dine-2,4-dione) and three degradation products from a North Carolina Piedmont aquic hapludult soil following a spray application of fungicides. Results suggest that pH, rain events, and method of application were the primary factors influencing vinclozolin's post-application transformation into three degradation products. Other factors such as the presence of clay and soil organic matter, moisture and microbes were investigated for their potential role in vinclozolin's degradation and fate. One metabolite, 2-[(3,5-dichlorophenyl)-carbamoyl]oxy-2-methyl-3-butenoic acid ("M1"), appears to be formed by base-catalyzed hydrolysis mediated by soild particle surfaces and microbial enzymes. The greatest M1 production appears to increase with higher soil pore fluid pH levels and when the fungicide incorporated into the soil. Reduction and acid-catalytic reactions also appear to play a role in dicarboximide degradation in the soil at lower pore fluid pH levels. The three degradation processes were not found to be mutually exclusive. Non-equilibrium partitioning coefficients and deposition velocities of the dicarboximides determined from the chamber results will also be presented.
This abstract has been reviewed in accordance with the Unites States Environmental Protection Agency peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Translocation and Redistribution of Pesticides Applied in the Residential Environment 11/12/2000
Falconer, R. L., R. G. Lewis, C. R. Fortune, F. T. Blanchard, AND A. Y. Yau. Translocation and Redistribution of Pesticides Applied in the Residential Environment. Presented at Society of Environmental Toxicology and Chemistry, Nashville, TN, November 12-16, 2000.
Abstract: Pesticides are introduced into the indoor environment for pest control by direct application (e.g., insect sprays and bombs). They are also applied outdoors on lawns, in gardens, or around house foundations to control weed and insect populations. Insecticides and herbicides applied outside the home can intrude into indoor living spaces by vapor penetration or spray drift and can be tracked inside by human and pets. Most pesticides applied indoors are semivolatile and vaporize from treated surfaces (e.g., carpets and baseboards). Both semi- and nonvolatile pesticides can be re-suspended into air on particles by human and pet activity. These pesticides tend to accumulate on indoor surfaces (particularly in carpet dust), in food, on dinnerware, and on children's toys where they may present exposure risks to humans, especially small children. In this study, we conducted multi-media residential monitoring to investigate the temporal and spatial distributions or pesticides applied by homeowners and commercial applicators following indoor crack and crevice and exterior perimeter treatments, including the first concurrent measurements on children's hands and toys. In participating households, pre- and post-application samples of indoor air at 10-cm and 75-cm above the floor (child's breathing zone), surface transferable and vacuum-dislodgeable floor residues, deposition on table tops and dinnerware, absorption by surrogate food, and residues on children's hands and toys were measured for pesticide residues. Enantiomeric analysis of several chiral pesticides was also done to determine chiral signatures. Results show the translocation of pesticides from the areas of application to surfaces accessible for human contact.
This work has been wholly or in part funded by the United States Environmental Protection Agency under contract 68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.
PRESENTATION Post-Application Exposure Potential to Pesticides in the Residential Environment 08/20/2000
Falconer, R. L., R. G. Lewis, C. R. Fortune, F. T. Blanchard, AND A. Y. Yau. Post-Application Exposure Potential to Pesticides in the Residential Environment. Presented at 220th ACS National Meeting, Washington, DC, August 20-24, 2000.
Abstract: A study to investigate the temporal and spatial distributions of pesticides applied by homeowners and commercial applicators for indoor crack and crevice treatments was initiated by the U.S. EPA in 1999. In participating households, pre- and post-application samples of indoor air at 10-cm and 75-cm above the floor (child's breathing zone), surface transferable and vacuum-dislodgeable floor residues, deposition on table tops and dinnerware, absorption by surrogate food, and residues on children's hands and toys were measured for pesticide levels. Results from the study demonstrate the nature and magnitude of translocation of pesticides from the areas of application to surfaces accessible for human contact. The post-application redistribution of pesticides within the home as well as sampling and analytical problems will be discussed. Results of enantiomeric analysis for chiral pesticides in the samples will be presented.
This work has been wholly or in part funded by the United States Environmental Protection Agency under contract 68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.
PRESENTATION Highly Sensitive Assay for Anticholinesterase Compounds Using 96 Well Plate Format 08/20/2000
Rogers, K. R. AND N. N. Mishra. Highly Sensitive Assay for Anticholinesterase Compounds Using 96 Well Plate Format. Presented at 220th ACS National Meeting, Washington, DC, August 20-24, 2000.
Abstract: One of the approaches for reducing uncertainties in the assessment of human exposure is to better characterize concentrations of hazardous compounds that may be present in our immediate environment. A significant limitation to this approach, however, is that sampling and laboratory analysis of contaminated environmental and biological samples, can be slow and expensive; thus, limiting the number of samples that can be analyzed within time and budget constraints. Faster, simpler, and more cost-effective field screening methods can increase the amount of information available concerning the location, source and concentration of pollutants present in the environment. Among the compounds of interest to EPA for human exposure assessment are pesticides. More specifically, insecticides from the organophosphate and carbamate classes are widely used in industrial and residential settings. These compounds often show high acute toxicity due to their inhibition of the enzyme acetylcholinesterase (AChE).
Although there have been a variety of chromatographic methods reported for detection of these compounds, these techniques are typically expensive and time-consuming. In addition, there have been a number of bioanalytical and biosensor methods reported based on inhibition of AChE. Although these methods show considerable promise, they are, for the most part, not well suited for screening large numbers of environmental samples. There are also several other issues that must be addressed with respect to the application of an AChE inhibition assay to environmental screening. More specifically, a number of commonly used organophosphate insecticides require metabolic activation to inhibit AChE. In addition, organophosphorus and carbamate insecticides (and their metabolites) vary widely in their ability to inhibit AChE (i.e., their relative response in these inhibition assays). We report a screening assay for organophosphorus and carbamate classes of insecticides that is convenient, rapid, simple and sensitive. Incorporated into the assay protocol is an oxidation step to convert parent insecticides to their oxon forms. In addition to IC50 values, relative inhibition values (compared to paraoxon) are also reported.

The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded this research and approved this abstract as a basis for an oral presentation. Mention of trade names or commercial products does not constitute endorsement or recommendation of these products by the EPA. The actual presentation has not been peer reviewed by EPA. NNM is currently a National Research Council Fellow.
PRESENTATION Electrochemical Technique for Detection of Tnt Using Disposable Screen-Printed Electrodes 08/20/2000
Pearson, R. AND K. R. Rogers. Electrochemical Technique for Detection of Tnt Using Disposable Screen-Printed Electrodes. Presented at 220th ACS National Meeting, Washington, DC, August 20-24, 2000.
Abstract: Nitroaromatic and nitroamine explosives have been found in the soil and water from many government military bases due to disposal, storage and weapons testing. Run-off from contaminated soil and water can enter groundwater and potentially contaminate drinking water for near-by communities. Other sources of contamination can come from production plants and storage of explosives. With the closing of military bases throughout the U.S. and Europe, contamination will need to be assessed and remediated before the land and water can be used. The application of rapid and inexpensive field screening techniques facilitate more effective decisions during characterization and remediation processes. Field analytical techniques specific for TNT will also be of benefit in monitoring phytoremediation of explosives from contaminated soils.
A variety of laboratory-based methods have been reported for the measurement of explosives in contaminated environmental media [1,2]. A number of field methods have also been reported [3,4]. The methods that are based on chemical or immunochemical reactions (primarily rapid field methods) tend to show significant cross-reactivities with other contaminants. In addition, these methods can be somewhat complex and require expensive supplies and instrumentation. Presented in this abstract is a particularly simple, rapid, sensitive and potentially cost-effective technique for detection of TNT using screen-printed thick film electrodes coupled with SWV.

The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), funded this research and approved this abstract as a basis for an oral presentation. Mention of trade names or commercial products does not constitute endorsement or recommendation of these products by the EPA. The actual presentation has not been peer reviewed by EPA
PRESENTATION Factors Effecting Exposures to Vocs During Commuting in California 10/24/2000
Sheldon, L. S., A. W. Rea, A. F. Vette, C. E. Rodes, D. Whitaker, P. Jenkins, S. Hui, AND S. Freun. Factors Effecting Exposures to Vocs During Commuting in California. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: On the average, Californian's spend between one and three hours each day commuting. The contribution from in-vehicle exposures to air toxics may be a significant component of total air exposure. Although pollutant concentration data are important for exposure assessments, only limited data exist for passenger vehicles. To address this limitation, a study was conducted to measure concentrations of selected air toxics during commuting. Thirteen volatile organic chemicals (VOCs), including 1,3-butadiene, benzene, and MTBE were measured inside two vehicles during 32 driving trips in the cities of Los Angeles and Sacramento. Two-hour integrated samples were collected concurrently inside the vehicles, just outside the vehicle, along the roadway where the vehicle traveled, andat ambient monitoring sites. The driving scenarios were designed to evaluate the association between in-vehicle pollutant levels and factors such as the carpool lane, traffic congestion, vehicle type, roadway type, time of day, and ventilation setting.
In-vehicle pollutant levels were generally higher in Los Angeles than Sacramento. In Los Angeles, the average in-vehicle concentration of benzene and MTBE range from 10 to 22 g/m3 and 20 to 90 g/m3, respectively. In general, VOC concentrations were similar inside and outside of the vehicle. Vehicle VOC concentrations were higher than at roadway sites which were higher than at the ambient site. Vehicle type and ventilation setting had little effect on in-vehicle concentrations. Other factors such as roadway type and traffic density did have an effect. Details on the exposure estimated during commuting and factors that affect exposure will be given.

This work was not funded by the U.S. Environmental Protection Agency, and therefore, the contents do not necessarily reflect the views of the Agency and no official endorsement should be inferred.
PRESENTATION Determining Particle Emission Source Strengths for Common Residential Indoor Sources Using Real-Time Measurements and Piecewise-Continuous Solutions to the Mass Balance Equation 10/24/2000
Ott, W. R., P. Switzer, N. Klepeis, V. Zartarian, AND M. Brauer. Determining Particle Emission Source Strengths for Common Residential Indoor Sources Using Real-Time Measurements and Piecewise-Continuous Solutions to the Mass Balance Equation. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Abstract: A variety of common activities in the home, such as smoking and cooking, generate indoor particle concentrations. Mathematical indoor air quality models permit predictions of indoor pollutant concentrations in homes, provided that parameter values such as source strengths and decay rates are known. This paper investigates the use of piecewise-continuous solutions to the indoor mass balance model in conjunction with real-time measurements during experimental "controlled releases" of common indoor sources to estimate the values of source strength parameters. The real-time experimental data include mass concentrations for particles less than 2.5 micrometers (PM-2.5) and less than 3.5 micrometers (PM-3.5, or Respirable Suspended Particles, RSP) measured at 1-minute time intervals. The analysis of experimental data for determining source emission compares the "peak-estimation" approach with the "area-under-the-curve" approach, and discusses how nonuniformity of mixing caused by microplume activity can be addressed. The experiments include a variety of cooking activities (frying hamburgers, preparing steak dinner, cooking Cajun chicken, burning popcorn, making toast), smoking regular and "smokeless" cigarettes, and burning candles and incense. The results indicate that different types of cooking activity of the same food type produce great differences in source emission strengths, while repeatedly smoking the same brand of cigarette causes less variation in source emission rates. Characterizing cooking activity by a "char index" may be helpful for explaining the variability in source emissions for some foods, such as toast. Future research on exposure models may require better knowledge of indoor activity patterns and the manner in which the variability of activities affects indoor particle emissions, as well as stochastic methods to handle this variability of source emissions.
This abstract has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Environmental Technology Verification Program Advanced Monitoring Systems Outreach 09/12/2000
Fuerst, R. G. AND E. T. Hunike. Environmental Technology Verification Program Advanced Monitoring Systems Outreach. Presented at EPA/AWMA International Symposium on the Measurement of Toxic and Related Air Pollutants, Research Triangle Park, NC, September 12-14, 2000.
Abstract: Technology performance information must be effectively communicated if it is to be of value to prospective users. The U.S. Environmental Protection Agency has provided funding to the Environmental Technology Verification (ETV) program to provide a plan to verify the environmental performance characteristics of commercial-ready technologies and make that information available to the public. Since 1995 twelve individual technology areas have been chosen to cover the major technology areas needing advanced performance information. With the collection and evaluation of objective and quality assured data through third-party verification, ETV can provide potential buyers and regulators of technology with an independent and credible assessment of the performance of advanced technologies.
One of the ways ETV assures the quality of this program is through public outreach by contact with public stakeholders committees, the technology vendor community, and with State and Regional Outreach Activities. ETV provides documents of outreach activities through their Internet website including information such as: fact sheets describing the goal and purpose of the ETV program (including one in Spanish to provide some NAFTA countries with information about ETV); Memorandum of Understandings outlining mutual assistance with other entities, and a listing of previously verified technologies and those presently planned for or undergoing verification. The ETV website (www.epa.gov/etv) lists links with partner organizations who act as the third party verification organizations and also includes recent articles and press releases concerning ETV verification. International Outreach Activities on the website identifies the foreign countries that were hosted by individual pilots during various verification tests.

The ETV's Advanced Monitoring Systems (AMS) pilot, managed by the National Exposure Research Laboratory, covers one of the twelve pilot areas. The AMS pilot provides as part of its public Internet outreach: a Fact Sheet describing the specific operations of the pilot; a monthly newsletter discussing the current and future plans of the pilot's progress; technology profiles identifying and describing the verified technologies; stakeholder committee members and their affiliations; announcements of public meetings and summaries of previous meetings; and, the testing Protocols with the resulting verification statements and summaries in their entirety. All public information of the Advanced Monitoring Systems pilot can be located at Website address: www.epa.gov/etv/07/07_main.

This work has been funded fully or in part by the United States Environmental Protection Agency under an assistance agreement (CR 826215) to Battelle Memorial Institute. It has been subjected to Agency review and approved for publication.
PRESENTATION Data from EPA's UV Monitoring Network 07/02/2000
Shreffler, J. H. Data from EPA's UV Monitoring Network. Presented at 13th International Congress on Photobiology, San Francisco, CA, July 2-6, 2000.
Abstract: The U.S. Environmental Protection Agency, in cooperation with the National Park Service, has deployed 21 Brewer spectrophotometers in a national network for monitoring UV radiation from the sun. Seven of the Brewers are in urban areas, and fourteen are in National Parks (Figure 1). Raw data from the EPA UV Monitoring Network are easily accessible from a Web site. Rather simple filtering procedures can be used to eliminate questionable data. Correction of the response function for drift results in data in good agreement with output of a simple model (TUV). This paper illustrates the data adjustment and some results from the sites at RTP and Albuquerque, the latter having summer Diffey-weighted UV maxima at least 20% higher than those at RTP due to differences in altitude, ozone column, and aerosols.
PRESENTATION Movement and Deposition of Pesticides Within Residences After Interior and Exterior Applications 06/19/2000
Lewis, R. G., C. R. Fortune, F. T. Blanchard, AND D. E. Camann. Movement and Deposition of Pesticides Within Residences After Interior and Exterior Applications. Presented at AWMA 93rd Annual Conference and Exhibition, Salt Lake City, UT, June 19-23, 2000.
Abstract: In a study begun in 1999, the Environmental Protection Agency (EPA) investigated the temporal and spatial distributions of pesticides applied by homeowners and commercial applicators for indoor crack and crevice and exterior perimeter treatments. In each participating household, pesticide levels in indoor air at 10-cm and 75-cm above the floor (child's breathing zone) were measured pre- and post-application (0-14 days), along with dermal- and vacuum-dislodgeable floor residues, deposition on table tops and dinnerware, absorption by surrogate food, and residues on children's hands and toys. Surface soil residues were measured in the case of perimeter application. Monitoring devices and methods used include the URG 2500 air samplers (PM2.5 inlet), the HVS3 vacuum sampler, the PUF Roller, hand wipes and various techniques for deposition monitoring. Results from the study demonstrate the nature and magnitude of translocation of pesticides from the areas of application to surfaces accessible for human contact. This paper presents data from two indoor applications of diazinon and one outdoor (perimeter) application of chlorpyrifos. The post-application redisribution of the pesticides within the home and the exposure potentials via various routes (respiration, dermal contact, ingestion) are discussed.
This work has been wholly or in part funded by the United States Environmental Protection Agency under contract 68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.
PRESENTATION Intercomparison of Photochemical Mechanisms Using Response Surfaces and Process Analysis 05/19/2000
Tonnesen, G. S. AND D. J. Luecken. Intercomparison of Photochemical Mechanisms Using Response Surfaces and Process Analysis. Presented at Millenium NATO/CCMS International Technical Meeting on Air Pollution Modeling and Its Application, Boulder, CO, May 15-19, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Immunoassay Human Exposure Studies 12/14/2000
Van Emon, J. M., A. W. Reed, AND J. C. Chuang. Immunoassay Human Exposure Studies. Presented at American Chemical Society, Pacifichem 2000, Honolulu, HI, December 14-19, 2000.
Abstract: The Human Exposure Research Branch has developed several enzyme-linked immunosorbent assay (ELISA) methods to support human exposure assessment studies. Immunoassays to detect low levels (<10 ng/mL) of chlorpyrifos in food, track-in dirt and house dust have been applied to samples from dietary and indoor exposure surveys. Accelerated solvent extraction procedures followed by cleanup with solid phase extraction have been coupled with a chlorpyrifos ELISA for baby food and dietary samples. Recoveries greater than 90% were achieved for various food matrices. A methanol extraction with sonication followed by ELISA determination provided a streamlined method for analyzing chlorpyrifos from dust and track-in dirt. An immunoassay for the urinary metabolite of chlorpyrifos, 3,5,6-trichloro-2-pyridinol (TCP), has been optimized and evaluated using real-world samples from several monitoring studies. TCP is a major metabolite and environmental degradation product of the insecticide chlorpyrifos and the herbicide triclopyr. Comparative studies with GC/MS indicate a good correlation with the TCP assay at low ppb levels. The least detectable dose estimated for this assay is 0.01 ppb in hydrolyzed and diluted urine samples. Immunoassay results were compared with GC/MS measurements from occupational and nonoccupational exposure studies yielding good correlations (r=0.990 and r=0.970). An advantage of the ELISA method is the capability of rapidly providing exposure data during spray events.
This work has been funded wholly or in part by the U.S. Environmental Protection Agency and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Immunoassay Analysis for Chlorpyrifos in Foods 07/16/2000
Van Emon, J. M. AND A. W. Reed. Immunoassay Analysis for Chlorpyrifos in Foods. Presented at 37th Annual Pesticide Residue Workshop and Florida Foodborne Pathogen Analysis Conference, St. Petersburg, FL, July 16-21, 2000.
Abstract: Chlorpyrifos is widely used in agriculture on fruits and vegetables. The tolerances for chlorpyrifos on produce range from 0.1-8.0 ppm. Residue detection is commonly performed by gas chromatography following various cleanup procedures. However, the required cleanup can make the entire analytical process laborious and time-consuming. We have developed streamlined approaches for the detection of chlorpyrifos in various food matrices. One method utilizes a sonic extraction followed by dilution and detection with an enzyme linked immunosorbent assay (ELISA). Another approach is to perform the ELISA on dilutions of simple food homogenates. Recoveries for either procedure range from 74-95% for various baby foods (e.g., meat, vegetables and fruit). Cleanup with solid phase extraction was not necessary but can be used for more difficult matrices especially composite food samples. The ELISA could tolerate 2% acetonitrile and up to 5% methanol and had a detection range of 0.2-100 ng/mL. Chlorpyrifos levels of 5- 400 ppb could be determined using a 10 g sample. These methods are being extended to samples from a human exposure duplicate diet study.
This work has been funded wholly or in part by the United States Environmental Protection Agency and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Use of a Convection-Diffusion Model to Understand Gastrointestinal Absorption of Environmentally-Relevant Chemicals 12/03/2000
Rigas, M. L. AND E. A. CohenHubal. Use of a Convection-Diffusion Model to Understand Gastrointestinal Absorption of Environmentally-Relevant Chemicals. Presented at Society for Risk Analysis 2000 Annual Meeting, Arlington, VA, December 3-6, 2000.
Abstract: Understanding the factors that affect the gastrointestinal absorption of chemicals is important to predicting the delivered systemic dose of chemicals following exposure in food, water, and other media. Two factors of particular interest are the effects of a matrix to which the chemical might be bound during ingestion as well as the effects of other material ingested along with the toxicant of interest. We use transport analysis to examine molecular absorption from the small intestine. This will provide quantitative estimates of these factors not normally addressed in the clinical physiologically-based pharmacokinetic (PBPK) modeling literature. The theoretical model is based on an analysis designed to investigate pharmaceutical absorption. It includes factors such as lumenal and membrane diffusion, convection, degradation and desorption/dissolution. Lumenal and systemic concentrations are predicted in humans for two small lipophillic molecules, ibuprofen, and the organophosphate insecticide chlorpyrifos. The simulation results are compared with experimental data from the literature. The solution of the model equations has led to a parametric analysis elucidating the importance of different factors affecting the intestinal absorption of chemicals. The solution also provides a method to predict intestinal membrane permeability, Kp using single-point peak plasma concentration data following a known administered dose. It is expected that further analysis using the model and comparison with experimental results will aid in the development of generalizations regarding the model complexity needed to predict the fraction and rate of absorption for less well-studied chemicals.
This work has been funded wholly or in part by the United States Environmental Protection Agency and has been approved for publication.
PRESENTATION Proposed Suite of Models for Estimating Dose Resulting from Exposures By the Dermal Route 12/03/2000
CohenHubal, E. A., A. Bunge, L. M. Hanna, J. N. McDougal, AND A. M. Jarabek. Proposed Suite of Models for Estimating Dose Resulting from Exposures By the Dermal Route. Presented at Society for Risk Analysis 2000 Annual Meeting, Arlington, VA, December 3-6, 2000.
Abstract: Recent risk assessment guidance emphasizes consideration of mechanistic factors for influencing disposition of a toxicant. To incorporate mechanistic information into risk assessment, a suite of models is proposed for use in characterizing and quantifying dosimetry of toxic agents absorbed by the dermal route. The model suite was developed by identifying mass-transfer resistances in the dermal system. The most general (and most complex) model in the suite includes all potentially relevant resistances. The model treats the stratum corneum (SC), viable epidermis (VE), and subcutaneous fat as distributed-parameter compartments. Two-dimensional diffusion resulting from biphasic properties of the SC is also considered. The dermis is treated as a lumped-parameter compartment leading to systemic circulation. Irreversible binding is modeled in the SC; metabolism in theVE and the dermis. For most cases the full realization of this model will not be required, nor will data be available to implement it. Therefore, a series of reduced structures are also presented. These range from a distributed parameter model that only considers resistance in the SC to a model that treats the entire skin system as one well-stirred compartment linked to a systemic PBPK model. The model suite provides the flexibility required to conduct risk assessment on a wide variety of compounds. This is the first work that has addressed dermal dose-response dosimetry. Incorporating the dermal dosimetry model suite along with parallel suites for inhalation and ingestion routes into the risk characterization process will improve the mechanistic basis of assessments and, as a result, provide a platform for quantitative route-to-route extrapolation and calculation of aggregate estimates.
This work has been funded wholly or in part by the United States Environmental Protection Agency under contract no. 68-D-99-012 to Research Triangle Institute. It has been subjected to Agency review and approved for publication.
PRESENTATION Proposed Models for Estimating Relevant Dose Resulting from Exposures By the Gastrointestinal Route 12/03/2000
Rigas, M. L., W. L. Roth, AND A. M. Jarabek. Proposed Models for Estimating Relevant Dose Resulting from Exposures By the Gastrointestinal Route. Presented at Society for Risk Analysis 2000 Annual Meeting, Arlington, VA, December 3-6, 2000.
Abstract: Simple first-order intestinal absorption commonly used in physiologically-based pharmacokinetic(PBPK) models can be made to fit many clinical administrations but may not provide relevant information to extrapolate to real-world exposure scenarios for risk assessment. Small hydrophilic molecules may be absorbed rapidly by solvent drag in areas of the intestinal tract where net water absorption occurs. Lipophilic molecules may be absorbed more readily via other mechanisms and perhaps will be more well-absorbed if exposure occurs in a lipid matrix. We have developed a suite of four models ranging from the simple one compartment first-order model to a more complex tubular representation of the GI tract accounting mathematically for both convection and diffusion. The suite is designed to provide flexibility to the risk assessment process by best utilizing the disparate available data. By applying dimensional analysis to the solution of a convection-diffusion model of GI absorption, we can provide information as to what models and data would improve the risk assessment if data is available. Some non-linear factors that may be incorporated into model structures include but are not limited to active transport into or out of the GI lumen by transporter proteins and metabolism within intestinal tissue, possibly leading to local toxicity.
This work has been funded wholly or in part by the United States Environmental Protection Agency and has been approved for publication.
PRESENTATION Workshop on Unmix and Pmf as Applied to PM 2.5 02/14/2000
Willis, R. D. Workshop on Unmix and Pmf as Applied to PM 2.5. Presented at Workshop on UNMIX and PMF as Applied to PM 2.5, Research Triangle Park, NC, February 14-16, 2000.
Abstract: This report is the proceedings of a workshop convened to evaluate two new air quality receptor models, Positive Matrix Factorization (PMF) and UNMIX. The workshop was held in Research Triangle Park, NC, during February 14 - 16, 2000 and was sponsored jointly by EPA's Office of Research and Development (ORD) and Office of Air Quality Planning and Standards (OAQPS). The workshop evaluation of PMF and UNMDC was accomplished by examining the results of applying both models to two ambient PM2.5 data sets, one real and one synthetically generated. Both data sets were supplied in advance to a proponent of each model (UNMIX: Dr. Ron Henry, University of Southern California; PMF: Dr. Phil Hopke, Clarkson University). Each brought to the workshop the results of independently applying their model to both data sets. The report briefly summarizes the technical exchange and major conclusions reached during the workshop.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under Contract 68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document.
PRESENTATION Biomakers of Exposure and Metabolic Susceptibility to Fine Particle Air Pollution 10/24/2000
Lewtas, J., B. Binkova, S. R. Myers, J. Lenieek, P. Subrt, AND R. J. Sram. Biomakers of Exposure and Metabolic Susceptibility to Fine Particle Air Pollution. Presented at ISEA Conference, Monterey, CA, October 24-27, 2000.
Abstract: The influence of metabolic susceptibility (GSTM1 and NAT2 genotypes) on the association between personal air exposures and biomarkers of exposure, dose, and genetic damage were measured for 60 individuals in two regions exposed to ambient air in the Czech Republic. Personal monitors measured exposure to respirable air particles (<1.7 /um) and the adsorbed polycyclic aromatic hydrocarbons (PAH) for 24 h before collection of blood and urine. Blood samples were analyzed for trace metals, metabolic genotype, DNA adducts, protein adducts, chromosomal aberrations, and sister chromatid exchanges. Urine samples were analyzed for PAH metabolites, cotinine and mutagenic activity. At these environmental exposures to PM1.7 (0.8 -140ug/m3) and PAH (2 - 26 /ng/m3), personal exposures to PM1.7 were significantly correlated with persona] exposures to carcinogenic PAH (r= 0.79, p< 0.0001, n=60), total urinary PAH metabolites (r= 0.48, p= 0.0002, n=58), and two of the trace element levels in blood, selenium (r= 0.55, p< 0.0001, n=60) and lead (r= 0.39, p = 0.003, n=58). DNA adduct levels were significantly and linearly correlated with PAH exposure for the nonsmokers (r=0.36, p<0.05(), n=28) with either GSTMl(r=0.59, p<0.005, n=21) or NAT2 rapid (r=0.47, p<0.057, n=17) genotype present. There was a significant increase in correlation between personal PAH exposure and urinary PAH metabolites for NAT2 slow acetylators (r=0.58, p=0.001) compared to NAT2 rapid and GSTM1 genotypes. This suggests that variations in metabolic genotype account for some of the inter-individual variability observed in human biomarker measurements. The urinary PAH metabolites and trace element levels in blood provide potential source tracers for apportioning the sources of human exposure to fine particles. The selenium was associated with high sulfur coal and lead with the leaded gasoline in use during this study. The individual PAH profile is consistent with the sources of PAH in this region.
This work has been funded by the US Environmental Protection Agency. It has been subjected to Agency review and approved/or publication
PRESENTATION Human Exposure Analysis, An Interdisciplinary Science 09/20/2000
Wilson, N. K. Human Exposure Analysis, An Interdisciplinary Science. Presented at Math Department, Duke University, Durham, NC, September 20, 2000.
Abstract: The relatively new and expanding field of human exposure analysis has its genesis in the environmental movement and the interest of scientists and the public in understanding the interaction between anthropogenic and biogenic chemicals and people. The universe is full of chemicals. Most of these chemicals are not harmful to people, animals, plants, and the environment. In fact they are the very stuff of which we and our surroundings are made. A few chemicals may be harmful, provided there is a source, transport in the environment, a receptor such as a person, contact between the receptor and the chemical, and a level high enough to produce a deleterious health effect. If such an effect could occur, then risk assessment and risk management may be necessary. The science of human exposure assessment deals with several distinct aspects that underlie the risk characterization process. These are the source, the environmental pathway, environmental concentrations, human exposures, and dose. There is considerable overlap between exposure assessment and effects assessment in the areas of human exposures and dose.
A specific example of current human exposure research at the National Exposure Research Laboratory is a pilot study on preschool children's exposures to low levels of common contaminants that may be found in their everyday surroundings. This study, "Children's Total Exposures to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP)," is taking place now in several North Carolina and Ohio counties. Very little data are available on young children's exposures, and without such data on when, where, how, to what, and to how much children may be exposed, scientists can neither understand exposures nor model them to develop estimates of potential risk. Thus CTEPP has two objectives: (1) To measure the aggregate exposures through multiple pathways of a set of preschool children in several North Carolina and Ohio counties to a suite of persistent pollutants in their everyday environments, and (2) To apportion the exposure pathways and to identify and formulate the important hypotheses to be tested in future research. About 260 children will participate in CTEPP. Field sampling began in North Carolina in July 2000. The entire study will take place over approximately three years.

This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
PRESENTATION Environmental Immunochemistry at the U.S. EPA, National Exposure Research Laboratory's Human Exposure Branch 09/25/2000
Van Emon, J. M. Environmental Immunochemistry at the U.S. EPA, National Exposure Research Laboratory's Human Exposure Branch. Presented at UN/International Atomic Energy Agency Meeting, Vienna, Austria, September 25-28, 2000.
Abstract: Immunoehemical methods are responding to the changing needs of regulatory and monitoring programs and are meeting new analytical challenges as they arise. Recent advances in environmental immunoehemistry have expanded the role of immunoassays from field screening methods to highly quantitative procedures that can compete with chromatographic methods in the laboratory.
The first field trial of an immunoassay under the EPA Superfund Innovative Technology Evaluation (SITE) Program was conducted by the immunoehemistry research program of the U.S.EPA, NERL-Las Vegas. Four immunoassays to detect pentachlorophenol were evaluated and compared with a gas chromatography/mass spectrometry (GC/MS) method. Much was learned from this first field trial including appropriate quality control measures, data comparability, and how to perform a sensitive analytical method at a contaminated site. This study has become a model for subsequent field trials including immunoassays for the polychlorinated biphenyls (PCBs). Soil samples collected from a Superfund site were analyzed by a quantitative 96-well plate enzyme-linked immunosorbent assay (ELISA) developed by the NERL-Las Vegas. The performance of the ELISA was compared with that of gas chromatography (GC) using an electron capture detector (ECD). Very limited cross-reactivity was seen with 37 structurally related co-contaminants. Three extraction procedures were evaluated: an abbreviated methanol shake procedure, supercritical fluid extraction samples extracted by SFE and by Soxhiet were in close agreement with (SFE) with carbon dioxide, and Soxhiet extraction with methanol. The GC/ECD results. The simple methanol shake method yielded lower ELISA results, supporting the importance of extraction procedures in the overall analysis scheme.

This work has been funded wholly or in part by the U.S. Environmental Protection Agency and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Retirement Facility 09/12/2000
Conner, T. L., G. A. Norris, M. S. Landis, AND R. W. Williams. Retirement Facility. Presented at EPA/AWMA International Symposium on the Measurement of Toxic and Related Air Pollutants, Research Triangle Park, NC, September 12-14, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Radiocarbon Measurements on PM-2.5 Ambient Aerosol 10/24/2000
Lewis, C. W., G. A. Klouda, AND W. D. Ellenson. Radiocarbon Measurements on PM-2.5 Ambient Aerosol. Presented at NARSTO 2000 Tropospheric Aerosols: Science and Decisions in an International Community, Queretaro, Mexico, October 23-26, 2000.
Abstract: Radiocarbon (14C) measurements provide an estimate of the fraction of carbon in a sample that is biogenic. The methodology has been extensively used in past wintertime studies to quantify the contribution of wood smoke to ambient aerosol. In summertime such measurements can provide an upper limit on the contribution of biogenic volatile organic compounds, through gas-to-particle conversion, to ambient PM-2.5 aerosol. Since this component of PM-2.5 is virtually uncontrollable, its quantification is important in the formulation of realistic overall control goals for summertime PM-2.5. Ambient PM-2.5 ambient samples have been collected during various large U.S. summertime field studies for subsequent radiocarbon analysis. Results will be reported for samples from Azusa, California (1997 Southern California Ozone Study) and Nashville, Tennessee (1999 Southern Oxidant Study).
This work has been funded wholly or in part by the United States Environmental Protection Agency under Interagency Agreement No. 13937923 to the National Institute of Standards and Technology, and Contract No. 68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.
PRESENTATION Comparison of Integrated Samplers for Mass and Composition 12/15/2000
Solomon, P. A., K. Baumann, E. Edgerton, L. A. Gundel, R. Tanner, D. J. Eatough, H. Maring, D. Savoie, AND S. Natarajan. Comparison of Integrated Samplers for Mass and Composition. Presented at AGU Fall Meeting, San Francisco, CA, December 15-19, 2000.
Abstract: The primary objective of EPA's Atlanta Supersites Project was to compare and evaluate a wide variety of samplers from time-integrated mass only monitors, to integrated and semi-continuous chemical speciation samplers, to single particle mass spectrometers. This paper will describe the evaluation/comparison of the 24-hour average integrated PM2.5 chemical speciation samplers and 12-hour average MOUDI samplers averaged to 24-hours. Samplers include those available for EPA's National Chemical Speciation Network, plus several used in the public/private research sector. The latter include two slightly different Particle Composition Monitors (PCM), two slightly different PC-BOSS samplers, and a MOUDI sampler, as well as the IOGAP sampler for organic carbon. Fifteen samples were collected on odd calendar sampling days. The comparison will include mass and its major chemical components (sulfate, nitrate, ammonium, organic carbon, and elemental carbon) and minor and trace elements (those typically observed by XRF). PM2.5 chemical speciation data will be compared to a relative reference value calculated as the average across all integrated samplers on a species-by-species basis and relative to an FRM where chemical composition is determined and to a VAPS sampler containing denuders and reactive filters for collecting semi-volatile species (nitrate and semi-volatile organic carbon) with minimal bias. The FRM will be used for comparison of stable species (trace metals and sulfate) while the VAPS will be an additional relative reference for nitrate and organic carbon.
This work has been funded wholly or in part by the United States Environmental Protection Agency. Portions of the work were performed under Contract Nos. 68-D5-0040 and 68-D-00-206 by Research Triangle Institute. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION An Overview of the Objectives and Design of the '99 Atlanta Supersite Experiment 12/15/2000
Chameides, W. L., P. A. Solomon, C. S. Kiang, D. Mikel, E. Cowling, E. Ericedge, J. Jansen, P. McMurry, J. Meagher, S. Hering, AND T. Bahadori. An Overview of the Objectives and Design of the '99 Atlanta Supersite Experiment. Presented at AGU Fall Meeting, San Francisco, CA, December 15-19, 2000.
Abstract: During the Summer of 1999, a 4-week intensive field campaign was conducted at a site on Jefferson Street in Midtown Atlanta. The campaign, the 1999 Atlanta Supersites Experiment, was carried out under the direction of the Southern Oxidants Study and represented the first of U.S. EPA's Supersite activities (Albritton, D.L. and D.S. Greenbaum, "Atmospheric Observations: Helping Build the Scientific Basis for Decisions Related to Airborne Particulate Matter," U.S. EPA, October, 1998). The Atlanta Supersites Experiment involved an international team of over 100 scientists and engineers. It brought together a wide array of commercially available and state-of-the science atmospheric-chemical and meteorological measurement equipment to comprehensively address issues related to the measurement and characterization of fine particles in polluted or urban atmospheres.
This work has been funded wholly or in part by the United States Environmental Protection Agency. Portions of the work were performed under Contract Nos. 68-D5-0040 and 68-D-00-206 by Research Triangle Institute and Cooperative Agreement CR 824843. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Intercomparision of Semi-Continuous Measurements of Nitrate and Sulfate at the EPA Atlanta Supersite, August 1999 12/15/2000
Weber, R., D. Orsini, Y. Duan, Y. N. Lee, F. Brechtel, P. Klotz, H. ten Brink, P. K. Dasgupta, S. Hering, E. Edgerton, P. A. Solomon, AND K. Baumann. Intercomparision of Semi-Continuous Measurements of Nitrate and Sulfate at the EPA Atlanta Supersite, August 1999. Presented at AGU Fall Meeting, San Francisco, CA, December 15-19, 2000.
Abstract: The Atlanta Supersite was one of the first Environmental Protection Agency (EPA) Supersites dedicated to the study of fine particles (PM2.5). The study involved intensive measurements during the month of August 1999, at a site situated near the center of Atlanta. One of the studies major objectives was to provide a platform for testing and intercomparing newly developed techniques for the measurement of fine particle chemical composition. As part of this study, five state-of-the art instruments were deployed for rapid on-line measurements of PM2.5 nitrate and sulfate concentration. Sampling rates for these instruments ranged from 7 minutes to 1 hour. The various instruments deployed were: a denuder difference approach (Edgerton), two systems based on condensation of water vapor onto particles followed by ion-chromatography (IC) analysis of the collected droplets (Slanina and Weber/Lee), an automated filter collector with online extraction via water flushing and IC analysis (Dasgupta), and measurement of evolved gases from flash vaporization of particles collected by impaction (Hering).
During the one-month intensive, ambient concentrations of nitrate and sulfate varied significantly. Sulfate concentrations ranged from 0.1 to 70 micrograms per meter cubed. Nitrate concentrations were generally much lower, ranging from 0.1 to 5 micrograms per meter cubed. All the rapid measurements revealed a fine structure in the temporal variation of nitrate and sulfate that was not observed by the 12 and 24 hour integrated samplers.

These rapid measurements of nitrate and sulfate will be intercompared and also cross-compared with 12 and 24 hour integrated filter measurements of nitrate and sulfate (Solomon and Baumann).

This work has been funded wholly or in part by the United States Environmental Protection Agency. Portions of the work were performed under Contract Nos. 68-D5-0040 and 68-D-00-206 by Research Triangle Institute and Cooperative Agreement CR 824843. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION A New Tracer Method for Assessing Hand-to-Mouth Transfers of Pesticides 10/24/2000
Nishioka, M. G., R. Barnes, W. Ivancic, J. Sowry, AND E. A. CohenHubal. A New Tracer Method for Assessing Hand-to-Mouth Transfers of Pesticides. Presented at ISEA Annual Meeting, Monterey Pennisula, CA, October 24-27, 2000.
Abstract: A common food chemical with high fluorescence intensity is being used in an evaluation of dermal transfer efficiencies as a surrogate for indoor pesticides chlorpyrifos and synthetic pyrethroids. The fluorescence monitoring system is based on an Olympus digital camera and the Matrox data imaging software, the latter providing capabilites for both surface area integration and intensity quantification. Because of the fluorescence characteristics of the tracer compound, the monitoring system utilizes a standard fluorescent light bulb as the excitation source, thus eliminating concerns about the exposure of subjects to UVA and UVB radiation.
Sampling tools that are being used include J&J SOF-WICK gauze pads as deposition coupons, a modified PUF Roller tool with a removable PUF thin sleeve, and the EL Press sampler with Empore disks. Extraction of the tracer is accomplished using either ASE extraction with sub-critical water or manual squeeze techniques with water (for PUF) or a water:methanol mixture (for Empore). Recoveries are >80% with spike levels of 0.1-20 ug. Pesticides are extracted similarly and reconcentrated on a C18 cartridge before analysis.

This work has been wholly funded by the US Environmental Protection Agency under Contract No. 68-D-99-011 to Battelle. It has been subjected to Agency review and approved for publication.
PRESENTATION Sample Integrity of Volatile Organic Compounds Collected and Stored on Multiabsorbent Tubes and Analyzed Using An Auto Gc-MS System 09/12/2000
Oliver, K. D., H. H. Jacumin Jr., E. H. Daughtrey Jr., AND W. A. McClenny. Sample Integrity of Volatile Organic Compounds Collected and Stored on Multiabsorbent Tubes and Analyzed Using An Auto Gc-MS System. Presented at International Symposium on Measurement of Toxic and Related Air Pollutants, Research Triangle Park, NC, September 12-14, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Chemical Mass Balance Model: EPA-Cmb8.2 09/12/2000
Coulter, C. T., R. A. Wagoner, AND C. W. Lewis. Chemical Mass Balance Model: EPA-Cmb8.2. Presented at International Symposium on Measurement of Toxic and Related Air Pollutants, Research Triangle Park, NC, September 12-14, 2000.
Abstract: The Chemical Mass Balance (CMB) method has been a popular approach for receptor modeling of ambient air pollutants for over two decades. For the past few years the U.S. Environmental Protection Agency's Office of Research and Development (ORD) and Office of Air Quality Planning and Standards (OAQPS) have collaborated to develop a new generation of CMB software, CMB8. Developmental work was initiated under EPA contract by the Desert Research Institute and is being continued by Pacific Environmental Services. The current version, EPA-CMB8.2, incorporates the upgrade features that CMB8 has over CMB7, but also addresses problems identified with CMB8 and adds enhancements for a more robust and user-friendly system. EPA-CMB8.2 features include: (1) full use of Windows (32-bit) capability for file access/management, (2) a tabbed-page interface that facilitates the sequence of steps for doing a CMB calculation, (3) multiple indexed arrays for selecting fitting species and sources, (4) versatile display capability for ambient data and source profiles, (5) mouse-overs and on-line help screens, (6) increased attention to volatile organic compounds (VOC) applications, (7) correction of some CMB7 and CMB8 flaws, (8) more options for input and output data formats, (9) addition of a more accurate least squares computational algorithm, (10) a new treatment of source collinearity, and (11) choice of criteria for determining best fit.
The information in this document has been funded wholly or in part by the United States Environmental Protection Agency under Purchase Order No. 9D-1844-NTSA to Pacific Environemental Sciences. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Distribution of Pesticides and PAH Residues in Aged Residential Carpeting 10/24/2000
Fortune, C. R., F. T. Blanchard, W. D. Ellenson, D. E. Camann, AND R. G. Lewis. Distribution of Pesticides and PAH Residues in Aged Residential Carpeting. Presented at 2000 Annual Meeting of the International Society of Exposure Analysis, Pacific Grove, CA, October 24-27, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Flow and Aerosol Transport Around a Child-Size Manikin 11/06/2000
Heist, D. K., A. D. Eisner, W. J. Mitchell, AND R. W. Wiener. Flow and Aerosol Transport Around a Child-Size Manikin. Presented at 19th Annual AAAR Conference, St. Louis, MO, November 6-10, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Transport and Transformation of a Semi-Volatile Fungicide from Soil to the Atmosphere: Chamber Design and Fabrication 10/31/2000
Vallero, D. A., L. Stockburger, J. L. Farnsworth, AND J. J. Peirce. Transport and Transformation of a Semi-Volatile Fungicide from Soil to the Atmosphere: Chamber Design and Fabrication. Presented at Region/Office of Research and Development Poster Session, Chicago, IL, October 31-November 1, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Transport and Transformation of a Semi-Volatile Fungicide from Soil to the Atmosphere: Dicarboximide Results 10/31/2000
Vallero, D. A. Transport and Transformation of a Semi-Volatile Fungicide from Soil to the Atmosphere: Dicarboximide Results. Presented at Region/Office of Research and Development Poster Session, Chicago, IL, October 31-November 1, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Enhanced Concentration and Analysis Method for Measuring Water Soluable Endogenous Compounds in Human Breath 04/01/2000
Pleil, J. D., M. Colon, AND A. B. Lindstrom. Enhanced Concentration and Analysis Method for Measuring Water Soluable Endogenous Compounds in Human Breath. Presented at American Chemical Society 221st National Meeting, San Diego, CA, April 1-5, 2001.
Abstract: Exhaled human breath analysis has become a standard technique for assessing exposure to exogenous volatile organic compounds (VOCs) such as trihalomethanes from water chlorination; aromatics, hydrocarbons, and oxygenates from fuels usage; and various chlorinated solvents from industrial or consumer exposures. The time dependent breath concentration changes during exposure (uptake) and post-exposure (eliminations) periods have been employed to estimate biological parameters such as blood levels, compartmental residence times, tissue capacities, peak exposure, minimum total does, and metabolic clearance rates. In recent studies of fuels and solvent exposures, breath measurement has become a non-invasive surrogate for blood measurements.
The success of using breath as a "biological fluid" has created interest in measuring additional compounds that may serve as internally produced biomarkers of external chemical exposures which could serve as a simple, non-invasive exposure assessment tool for internal dose. Such biomarkers will most likely occur at very low concentrations compared to the exposure and will be very water soluble; these are two properties that make gas phase analysis difficult. We have developed a sampling and analytical method that accentuates the water soluble fraction of organic compounds in breath for GC/MS analysis. Multiple breaths are passed through special glassware at subambient temperature (-80 C); upon heating to 37 C, the condensed water is sparged with dry nitrogen into a standard 1-liter volume breath sampling container (SUMMA canister) also at -80 C. When warmed to room temperature, the canister becomes positively pressurized and is then analyzed as a normal single breath sample, yet contains an elevated amount of the polar volatile organic compounds as trapped from 40 or 50 breaths. This allows more detailed analysis of the normally occurring metabolic products as well as putative biomarkers of exposure in breath.

To date, we have identified a variety of compounds in normal (healthy) adults that include C3 to C9 n-aldehydes, C3 and C4 branched aldehydes, alcohols, terpenoids, ethers, acetates, etc. have been tentatively identified and work continues to unambiguously confirm as many compounds as possible. In the long run, we anticipate using pattern of endogenously produced compounds expressed in breath as an indicator of external exposure.

This work has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review process and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Use of Metal-and Fluorescein-Tagged Materials to Study Settled Particles Exposure Pathways 04/01/2000
Harper, S. L., J. T. Antley, J. Giglio, AND R. W. Vanderpool. Use of Metal-and Fluorescein-Tagged Materials to Study Settled Particles Exposure Pathways. Presented at American Chemical Society 221st National Meeting, San Diego, CA, April 1-5, 2001.
Abstract: Through the use of ten size ranges of tagged materials (Antley et. al., 2000a), inductively coupled plasma- mass spectrometry (ICP-MS) and flourometry are being used to study the movement of settled particles in the indoor environment, exposure pathways, and the collection efficiency of surface samplers. Particle-bound contaminants in housedust and tracked-in soil represent potentially significant exposure hazards for both children and adults. Children and adults can be exposed to housedust by direct dermal contact to dust on floors (hard surface and carpeting) and elevated horizontal surfaces (furniture and countertops), and by inhalation from housedust resuspended by normal activities such as walking on flooring, especially carpeting. Additionally, young children may add an ingestion route if mouthing activities are included. The movement of housedust from the original source (settling from air, track-in from outside) to the ultimate exposure location is a function of particle size and dust character. During this migration, the dust and soil may become contaminated with liquid-applied pesticides, or the particles, such as lead-based paint or particle-form pesticides.
Estimates of exposure of this settled and tracked-in dust are typically obtained from surface samplers. Representativeness of the sample collected to the actual contamination to which humans are exposed must be known. Research indicates that this exposure is related to the particle size. To date, the collection performance of many surface samplers for various sizes of particle-bound contaminants have not been well characterized and therefore the representativeness of the samples being collected is uncertain.

A laboratory technique has been developed (Antley et. al., 2000b) to generate reference surfaces of particles of known characteristics which consists of a dry particle distribution system using tagged materials of sizes ranging from <1 to 500 micrometers physical diameter (< 1 micron to 850 microns aerodynamic diameter). The computer-controlled positioning system is capable of moving the aerosolization system over the test surface to generate spatially uniform deposits for total surface loading of 0.100 to 19.600 g/m2 with deposition uniformity of 20% CV or less. The deagglomerated particles are deposited at natural terminal settling velocities on hard or soft surfaces. These surfaces are then used for studies of surface sampler characteristics and dermal transfer and may be used for resuspension, re-entrainment, and particle mobility and fate studies.

Use of a different metal for each particle size fraction allows for use of polydisperse mixtures while retaining the ability to perform assessments as a function of particle size. Internal standards are used as performance indicators for the ICP-MS as well as indicators of loss during sample collection and processing. Use of fluorescein tagged materials for discrete particle size range experiments permits the analyses of masses lower than gravimetric determinations of untagged materials.

This work has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review process and approved for presentation and publication. Mention of tradenames or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION (Cz)BIOMARKERS of Exposure to Particulate Air Pollution in the Czech Republic 10/03/2000
Lewtas, J., B. Binkova, I. Miskova, P. Subrt, J. Lenicek, AND R. J. Sram. (Cz)BIOMARKERS of Exposure to Particulate Air Pollution in the Czech Republic. Presented at Teplice Program Conference, Prachatice, Czech Republic, October 3-5, 2000.
Abstract: The use of biomarkers in the Teplice Program, provided a key tool to relate health outcomes to individual personal exposures and to provide measures of confounding exposures. This research program on the health effects of air pollution studied a population living in the heavily industrialized district of Teplice in North Bohemia and compared the exposure and health of this population to that of a non-industrialized district, Prachatice, in Southern Bohemia. The studies included characterization of the environmental and personal air pollution exposure, biomarkers, and studies on reproductive, respiratory, and neurobehavioral effects. Biomarkers were measured in blood , urine, placenta, and sperm. The biomarkers included measures of exposure (e.g., urine metabolites and blood metals), dose (e.g., DNA adducts), DNA damage, genetic and cytogenetic effects, and susceptibility. During winter temperature inversions, unusually high concentrations of a complex mixture of air pollutants were measured, including fine particles, genotoxic organic compounds, and toxic trace elements. This population, however, was also exposed to multiple pollutants via all pathways, and including pollutants resulting from environmental exposures, occupational exposures, and personal habits (e.g., tobacco and alcohol use). Longitudinal and repeated measures used individuals as their own control to examine the influence of environmental exposures as they changed over time and season. Chronic and seasonal exposures to elevated air pollution in the Teplice District were shown to have serious adverse respiratory health consequences for children and reproductive effects in adults. Elevated levels of air pollutants, even for short-term winter inversions resulted in measurable uptake, metabolism, and excretion of polycyclic aromatic hydrocarbons, increased blood concentrations of toxic metals, and resulted in DNA damage. Results of the exposure, biomarker, and health studies indicated that environmental exposure to a complex mixture of air pollutants resulted in significant elevations in personal exposure, uptake, excretion of pollutants and DNA damage.
This paper has been reviewed in accordance with the US Environmental Protection Agency's peer and administrative review policies and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PRESENTATION Exposure to Dose Models: Their Uses in Helping Access Relevant Dose in Children 05/01/2000
Blancato, J. N. Exposure to Dose Models: Their Uses in Helping Access Relevant Dose in Children. Presented at Children's Health Symposium of the Office of Environmental Health Hazard Assessment of the State of California, Oakland, CA, May 1-2, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Natural Convection Effect on Personal Aerosol Samples 11/06/2000
Eisner, A. D., Z. E. Drake, D. K. Heist, AND W. J. Mitchell. Natural Convection Effect on Personal Aerosol Samples. Presented at 19th Annual AAAR Conference, St. Louis, MO, November 6-10, 2000.
Abstract: There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
PRESENTATION Mortality Among Farmers and Spouses in the Agricultural Health Study 09/22/2000
Blair, A., D. Sandler, R. Tarone, J. H. Lubin, K. W. Thomas, C. Lynch, S. H. Zahm, N. Rothman, AND M. Alavanja. Mortality Among Farmers and Spouses in the Agricultural Health Study. Presented at American College of Epidemiology Annual Meeting, Albuquerque, NM, September 22-24, 2002.
Abstract: In the Agricultural Health Study we evaluated the mortality experience of 52,395 farmers and 32,347 of their spouses in Iowa and North Carolina obtain information on cancer and other chronic disease risks from agricultural exposures and other factors associated with rural lifestyle.
Standardized mortality ratios (SMRs) adjusted for race, gender, age, and calendar time were computed for the prospective cohort, using the general population in each state as the referent. Results: After an average follow-up of 3.7 years, the SMRs for most causes of death were significantly less than 1.0. Significant deficits were observed for all causes (SMR=0.5), all cancers combined (SMR=0.5), and for cancers of the lung (SMR=0.3), female genital organs (SMR=0.4), prostate (SMR=0.6) and bladder (SMR=0.6), as well as diabetes (SMR=0.3), cardiovascular disease (SMR=0.5), and chronic obstructive pulmonary disease (SMR=0.2). Non-significant excesses involving at least 3 deaths occurred for liver cancer (SMR=2.1), multiple myeloma (SMR=1.6), leukemia (SMR=1.4), and Parkinson's disease among spouses (SMR=2.7). Among farmers elevated SMRs were noted for Hodgkin's disease (SMR=2.9) and cancer of the thyroid gland (SMR=2.9), and non-motor vehicle accidents (SMR=1.1). Soft tissue sarcoma (SMR=1.1 for spouses; SMR=1.6 for applicators) was elevated in both groups. NHL had an SMR of 1.0 among applicators and spouses. Stratification by presence of livestock or corn on the farm, farm size, and duration of handling pesticides revealed no obvious mortality differences.

Despite a very low initial mortality experience compared to the general population, Agricultural Health Study farmers and their spouses appear to have rates for some cancers and chronic diseases that deserve continued monitoring and further scrutiny.

The U. S. Environmental Protection Agency through its Office of Research and Development partially funded and collaborated in the described paper. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an
EPA document.
PUBLISHED REPORT Dermal Transfer Efficiency of Pesticides from Turf Grass to Dry and Wetted Palms 03/20/2000
Clothier, J. M. Dermal Transfer Efficiency of Pesticides from Turf Grass to Dry and Wetted Palms. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-00/026 (NTIS PB2000-101992), 2000.
Abstract: This report presents results of a study to determine the transfer of three pesticides commonly used in residential lawn care from turf grass to human skin. Formulation of the insecticides chlorpyrifos and cyfluthrin and the fungicide chlorothalonil were applied to St. Augustine grass and allowed to dry for 24 hours. Deposition coupons were used to estimate initial surface loadings and the PUF Roller was to measure dislodgeable residues. After 24 hours, adult volunteers performed hand presses (left and right hands, palm only) with either dry or wetted skin. Both water and the participant's own saliva were used as wetting agents. The mean (six presses) transfer efficiencies for chlorpyrifos were 0.115% for water-wetted, 0.156% for saliva-wetted, and 0.046% for dry skin. Transfer efficiencies for the other two pesticides were much higher (3.06, 2.72% and 1.29% for chlorothalonil and 4.02%, 4.18% and 2.93% for cyfluthrin, respectively), but the same relationship was observed: no essential differences between saliva- and water-wetted skin and substantially lower transfer efficiencies for dry skin.
The work reported in this internal report was performed for the Exposure Methods and Monitoring Branch, National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, during the period March to August 1999 under Work Assignment IV-105 to ManTech Environmental Technology, Inc. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PUBLISHED REPORT Analysis of Aged in-Home Carpeting to Determine the Distribution of Pesticide Residues Between Dust, Carpet, and Pad Compartments 05/24/2000
Fortune, C. R., F. T. Blanchard, AND W. D. Ellenson. Analysis of Aged in-Home Carpeting to Determine the Distribution of Pesticide Residues Between Dust, Carpet, and Pad Compartments. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-00/030 (NTIS PB2000-101991), 2000.
Abstract: This report presents results of a study to determine the distribution of pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) between dust and carpet components in aged carpeting. Carpeting in eight homes in the Research Triangle Area, which were recruited on the bases of carpet age . In each household, two 1 m2 areas, one high-traffic and one low-traffic, were selected for sampling prior to carpet replacement. Each area was first subjected to sampling with the PUF Roller to determine dislodgeable residues, then sequentially vacuumed with the HVS3 and Hoover Deep-dust vacuum systems and the collected dust samples separately analyzed. Subsequently, the carpet areas were excised and the pile removed from the backing for separate extraction and analysis. The carpet pad under the sampled areas was likewise extracted and analyzed, as was dust collected from the flooring beneath the pad. Analyses of all samples for 39 neutral-extractable pesticides, PAHs and PCBs revealed that the major portions of the pollutants were within the carpet fibers, backing and pad.
The work reported in this document was performed for the Exposure Methods and Monitoring Branch, National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, during the period July 1997 to April 1999 under Work Assignments 47 and 76 of Contract 68-5-0049 by ManTech Environmental Technology, Inc., and by Southwest Research Institute under Subcontract 96-0049-01 to ManTech. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PUBLISHED REPORT Dermal Transfer Efficiency of Pesticides from New and Used Cut-Pile Carpet to Dry and Wetted Palms 05/25/2000
Camann, D. E. AND J. M. Clothier. Dermal Transfer Efficiency of Pesticides from New and Used Cut-Pile Carpet to Dry and Wetted Palms. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-00/028, 2000.
Abstract: This report presents results of a study to determine the transfer efficiencies from carpet to human skin of four pesticides commonly used for residential indoor insect control. Formulations of the insecticides chlorpyrifos, pyrethrin I and piperonyl butoxide were applied to new, cut-pile nylon carpeting by broadcast spray and allowed to dry for 4 hours. Deposition coupons were used to estimate initial surface loadings and the PUF Roller was to measure dislodgeable residues. After the 4-hour drying period, adult volunteers performed hand presses (left and right hands, palm only) with either dry or wetted skin. Water, an aqueous dioctylsulfosuccinate (DSS) surfactant solution, and the participant's own saliva were used as wetting agents. Transfer efficiencies for wetted palms were two to six higher than those for dry palms. The mean (six presses) transfer efficiencies for chlorpyrifos were 1.64% for water-wetted (W), 0.90% for saliva-wetted (S), 1.21% for DSS-wetted, and 0.48" for dry skin (D). Transfer efficiencies for the other two freshly-applied pesticides were higher in most cases (W = 2.50%, S - 1.87%, DSS = 1.39%, and D - 0.32% for pyrethrin I and W = 2.58%, S = 2.03%, DSS = 1.72%, and D = 0.44% for piperonyl butoxide). Transfer efficiencies for aged permethrin residues in used carpet of similar composition were on the same order as those observed for freshly-applied residues: 2.45% for palms moistened with water, 2.3% with saliva, and 0.6% for dry palms.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract 68-D5-0049 to ManTech Environmental Technology, Inc., and ManTech's subcontract 96-0049-01 to Southwest Research Institute. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
PUBLISHED REPORT Dermal Transfer Efficiency of Pesticides from New, Vinyl Sheet Flooring to Dry and Wetted Palms 07/06/2000
Clothier, J. M. Dermal Transfer Efficiency of Pesticides from New, Vinyl Sheet Flooring to Dry and Wetted Palms. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-00/029 (NTIS PB2000-101990), 2000.
Abstract: The USEPA is concerned about the exposure of humans to pesticide residues contained in or on various surfaces found within the home environment. Studies have been conducted to evaluate a variety of home surfaces for surface-dislodgeable residues, which are those that are most readily available for transfer to human skin. These surface residues are thereby available for ingestion by infants and toddlers through mouthing activities involving their fingers, hands, feet, and toys. In earlier studies designed to evaluate dislodgeable residue transfer of chlorpyrifos, pyrethrins, and piperonyl bu-toxide from carpet (Task 3 of Work Assignment III-76), moistened palms transferred between 3-6 times more residue from carpet than did dry palms. The emphasis in this study, therefore, was placed on determining whether the same relationship existed with residues transferred from pesticide-treated vinyl flooring unto dry and wetted palms.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract 68-D5-0049 to ManTech Environmental Technology, Inc., and ManTech's subcontract 96-0049-01 to Southwest Research Institute. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use
PUBLISHED REPORT Effectiveness of the PM 2.5 Federal Reference Method to Differentiate Fine and Coarse Mode Aerosol (a Response to Section 6102(e) of the Transportation Equity Act for the 21st Century 11/28/2000
Peters, T., J. T. Antley, R. W. Vanderpool, S. Natarajan, G. A. Norris, F. F. McElroy, P. A. Solomon, D. B. Gemmill, M. P. Tolocka, AND R. W. Wiener. Effectiveness of the PM 2.5 Federal Reference Method to Differentiate Fine and Coarse Mode Aerosol (a Response to Section 6102(e) of the Transportation Equity Act for the 21st Century. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-00/033 (NTIS PB2001-101909), 2000.
Abstract: This report is submitted in response to Section 6102(e) of the Transportation Equity Act for the 21st Century, which states:
"The Administrator shall conduct a field study of the ability of the PM2.5 Federal Reference Method to differentiate those particles that are larger than 2.5 micrograms [sic] in diameter. This study shall be completed and provided to the Committee on Commerce of the House of Representatives and the Committee on Environment and Public Works of the United States Senate no later than 2 years from the date of enactment of this Act."

While the concern about the ability of the Federal Reference Method to function as asserted is understandable, extensive data from multiple laboratory and field tests have established that the Federal Reference Method effectively differentiates between particles larger and smaller than 2.5 micrometers in aerodynamic diameter.

Extensive laboratory tests, conducted by the U.S. EPA and independent researchers, demonstrated that the reference method primary size separation hardware, the WINS impactor, provides selection of particles less than 2.5 micrometers in aerodynamic diameter. Furthermore, these evaluations showed conclusively the ability of the WINS to eliminate coarse particle intrusion when clean and after becoming dirty during routine field use. Three intensive field studies corroborated the laboratory findings.

Additional field studies are ongoing, in which existing and new or potentially superceding fractionation technologies are being challenged against a variety of ambient environmental conditions in an effort to more fully characterize sampler behavior

Part of the research described in this report was performed under Contract 68-D5-0040 to Research Triangle Institute, Research Triangle Park, NC. This report has been subject to the Agency's peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
PUBLISHED REPORT Development of International Standards for Air Quality Monitoring and Control 07/11/2000
U.S. Technical Advisory Group to ISO TC 146. Development of International Standards for Air Quality Monitoring and Control. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-00/064 (NTIS PB2000-106995), 2000.
Abstract: This report presents a description of the activities and accomplishments of the American Society for Testing and Materials' U. S. Technical Advisory Group (TAG) to the International Standards Organization's Technical Committee 146 on Air Quality. The purpose of the TAG is to represent the United States of America on matters involving the development and implementation of international standards on air pollution measurement and control. The TAG, which consists of technical experts from industry, government and academia, participate in the development of standards by writing, reviewing, and voting on adoption. The TAG has been instrumental in producing a large number of international standards based on EPA methods and other methods acceptable for use in the United States. This report describes the organization of ISO TC 146 and summarizes the activities of the TAG over the three-year period of Cooperative Agreement Grant CR824457, which provided funding for non-government technical representatives from the United States to travel to ISO and TAG meetings to participate in the development of standards to monitor and control air pollutants. Such standards help assure the maintenance of acceptable air quality for all nations.
The work described in this report covers the period from July 1,1997 to June 30, 2000.

The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the project described here under Cooperative Agreement Grant No. CR824457 to the American Society for Testing and Materials. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document.
PUBLISHED REPORT Development and Use of Rare Earth Tracers in the Modified Dry Particle Deposition System (Formerly "DUST" Chamber) 04/19/2000
Antley, J. T. AND J. Giglio. Development and Use of Rare Earth Tracers in the Modified Dry Particle Deposition System (Formerly "DUST" Chamber). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-00/005 (NTIS PB2001-100351), 2000.
Abstract: This report was submitted in partial fulfillment of Contract 68-D5-0040 by Research Triangle Institute under the sponsorship of the United States Environmental Protection Agency. This report covers a period from October 1, 1996 to September 30, 1999 and includes activities funded under Work Assignments I-12, II-24 and III-31.
The characterization of U.S. EPA's Dry Particle Deposition Chamber has been ongoing since the publication of EPA 600/R-96/106 ("Development and Evaluation of a Dry Particle Deposition Uniformity System with Transverse (DUST) to Generate Test Surfaces for House Dust Sampler Characterization, Re-entrainment, and Re-suspension Studies"). This report details the changes to the mechanical configuration, the operating procedures, the algorithms for data analyses, and the overall capabilities of the system.

Modifications of the hardware include design changes to the traversing system and the dust feeder carriage for increased stability.

Changes in operating procedures include a new dust plate loading mechanism and a new coupon configuration which provide a more representative measurement of the loaded surface. Tests in which the mass deposited on the surface was compared with the mass collected by the coupons allowed new algorithms to be developed for better prediction of surface loading.

Finally, a tagging procedure has been developed with the intended purpose of applying coatings of rare earth metals to discrete size fractions of surrogate dusts (Arizona Test Dust and glass beads). Extraction of metals from tagged particles may be analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to determine particle fate and transport as a function of discrete particle size ranges. Due to the sensitivity of ICP-MS, lower surface loadings (0.1 g/m2) are not theoretically possible, much lower then when analyzing deposits gravimetrically (3 g/m2)

The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under EPA Contract No 68-D5-0040 to Research Triangle Institute. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use
SITE DOCUMENT Strategic Plan for the Analysis of the National Human Exposure Assessment Survey (NHEXAS) Pilot Study Data 12/07/2000
Berry Jr., M. R., J. A. Graham, S. C. Hern, A. H. Ozkaynak, D. A. Pahl, J. J. Quackenboss, K. Hammerstrom, K. W. Leovic, G. L. Robertson, L. S. Sheldon, AND W. C. Steen. Strategic Plan for the Analysis of the National Human Exposure Assessment Survey (NHEXAS) Pilot Study Data. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-00/049, 2000.
Abstract: The Office of Research and Development (ORD) of the U.S. Environmental Protection Agency (EPA) initiated the National Human Exposure Assessment Survey (NHEXAS) in the early 1990's. It was a population-based pilot study of the exposure of over 500 people in three areas of the U.S. to metals, pesticides, volatile organic compounds, and other toxic chemicals. Measurements were made of the air people breathed, the foods and beverages they consumed, and the soil and dust in/near their home. Chemicals in their blood and urine were measured. The participants also completed questionnaires to help identify possible sources of exposures and to characterize activities that might contribute to exposure. To this date, NHEXAS remains the largest multimedia, multipathway, multichemical study of its kind. Key goals included evaluating the feasibility of conducting such a large study, documenting the population distribution of exposure to the chemicals examined, understanding the factors that contribute to high exposures, and improving the accuracy of exposure models.
Such a study produces a multitude of data that must be thoughtfully analyzed to realize its full potential. EPA's Science Advisory Board (SAB) recommended that EPA develop a strategy to analyze the data to ensure the optimal use of the data (EPA-SAB-IHEC-ADV-99-004, www.epa.gov/sab). Therefore, ORD developed this Strategic Plan. ORD began with a workshop at which about 70 scientific and policy experts from ORD, EPA program offices, EPA regions, other federal agencies, state health agencies, academia, and private institutions offered their suggestions on the most useful analyses of the NHEXAS pilot data. ORD used their thoughtful contributions as the basis to begin development of the Strategic Plan. The draft Plan was reviewed by the SAB (EPA-SAB-IHE C-00-018, www.epa.gov/sab). and made available to all EPA program offices and the public. This document has been revised based upon those recommendations.

The Strategic Plan describes projects in six topic areas: descriptive statistics; predictors of exposure and dose; spatial and temporal variability; aggregate exposure, pathway analysis, and cumulative risk; evaluation/refinement of current exposure models and assessments; and designing exposure studies. Criteria, founded on both the near- and long-term value to EPA, were established for ranking projects within each of these topic areas. The text describes how the criteria were applied to each project. The projects are described in the appendix. This prioritization will be used as a guide for ORD to implement the analyses. To expand the opportunities for all interested persons to get involved, the NHEXAS information is being prepared for entry into a publically available database, with appropriate metadata, in late 2001.

This document has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

 

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URL: http://cfpub.epa.gov/ordpubs/nerlpubs/nerlpubs_heasd_2000.cfm