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2007 Progress Report: Field Validation of the Sioutas Sampler and Leland Legacy Pump – Joint Project with EPA’s Environmental Technology Validation Program (ETV)
EPA Grant Number: R828678C013Subproject: this is subproject number 013 , established and managed by the Center Director under grant R824834
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Mickey Leland National Urban Air Toxics Research Center (NUATRC)
Center Director: Beskid, Craig
Title: Field Validation of the Sioutas Sampler and Leland Legacy Pump – Joint Project with EPA’s Environmental Technology Validation Program (ETV)
Investigators: Brinkman, Marielle C
Institution: Battelle
EPA Project Officer: Katz, Stacey
Project Period: January 2, 2001 through December 31, 2005 (Extended to December 31, 2008)
Project Period Covered by this Report: January 2, 2006 through December 31, 2007
RFA: Targeted Research Center (2004)
Research Category: Hazardous Waste/Remediation , Targeted Research
Description:
Objective:Under the auspices of the U.S. Environmental Protection Agency (EPA) through the Environmental Technology Verification (ETV) Program, this project involved verification testing of the Sioutas Personal Cascade Impactor Sampler (PCIS) and the Leland Legacy Pump. The verification test originally included four Subtasks: A) Pump Testing, B) Sampling Efficiency Comparisons, C) Sampling Metals in Ambient Air, and D) PCIS Ease of Use, Reliability and Subject Acceptance/Compliance. A fifth Subtask, the repeat of Subtask A using SKC-modified Leland Legacy Pumps, was added to the verification testing in August, 2006.
Project Background:
The primary objective of the study was to validate the Leland Legacy Pump and the Sioutas Sampler for personal exposure monitoring in a field study. Both of these devices were developed as a result of previous NUATRC research studies. The proposal was first discussed at the June 2005 SAP meeting. The NUATRC signed a two-year contract with Battelle, covering November 14, 2005 – October 31, 2006. This was extended through March 2007.
Preliminary Findings:
The Sioutas PCIS, operating in conjunction with the Leland Legacy® pump, is designed to separate and collect airborne PM in specific size ranges. The Sioutas PCIS was evaluated on the basis of comparability with the sampling efficiency of more well-known reference samplers; its ability to collect detectable levels of metals in ambient air; and its ease of use, reliability, and acceptance among volunteer subjects. Additionally, the Leland Legacy® pump was evaluated by itself on the basis of duration of operation on a single battery charge sampling at different pressure drops, and 24-hour performance sampling under moderate and extreme temperature and humidity conditions.
During the pump testing, four of the pumps failed and were returned to the vendor, SKC, for analysis. To solve the problem, SKC retrofitted the pumps with a new pin that has a hexagonal head. Both the original and retrofitted pumps were evaluated. This verification test included four separate evaluation phases and the results from each phase are summarized below.
Pump Testing
Both the original and retrofitted pumps sampled under an 11 inch H2O pressure drop via battery power for 28-35 hours in a moderate temperature and humidity (25°C and 30%) environment after a 15-hour battery charge. Due to repeated pump failures, the original pumps were not evaluated at high temperature-moderate humidity (40°C-60%) and high temperature-high humidity (40°C-90%) sampling environments. However, the retrofitted pumps sampled for the prescribed 24-hour period in both environments and maintained flow rates that were within 10% of the manufacturer’s recommended values.
None of the retrofitted pumps failed; even when sampling under extreme conditions that included backpressures and sampling periods that exceeded the manufacturer’s specifications. When sampling in extreme conditions, all of the retrofitted pumps sampled for longer than 26 hours before battery drain occurred. When sampling under a 15 inch H2O pressure drop, all of the retrofitted pumps sampled for 30 hours or more, whereas 3 of the 12 original pumps failed to sample for at least 24 hours. When sampling under the highest pressure drop tested, 19 inch H2O, all of the retrofitted pumps sampled for 26 hours or longer; whereas 5 of the 12 original pumps failed to sample for a least 24 hours.
On average, the original pumps operated for about 9-10 fewer hours when sampling under a 19 inch H2O pressure drop than under an 11 inch H2O, and sound levels increased by 2.1 dB. On average, the retrofitted pumps operated for about 6-7 fewer hours when sampling under a 19 inch H2O pressure drop than under an 11 inch H2O, and sound levels increased by 4.3 dB. The sound level of a single pump clad in the noise-reducing jacket and operating at the manufacturer’s recommended pressure drop ranged from 48-64 dB, which is a level similar to normal conversational speech (~60 dB). Sound levels measured for all four pumps operating at the highest pressure drop 19 inch H2O never exceeded 72 dB, which is equivalent to the sound level of a typical household vacuum cleaner.
The retrofitted pumps showed less variability than the original pumps in terms of flow rates and duration of operation over the sampling periods. Average duration of operation for the retrofitted pumps never deviated by more than 2.6% for the 11, 15, and 19 inch H2O tests; whereas it deviated by 5.6%, 33%, and 29%, respectively for the same tests, for the original pumps. Differences in average flow rate variability between the original and retrofitted pumps were less pronounced as average flow rates never deviated by more than 5.0% for the original pumps and not more than 2.1% for the retrofitted pumps.
Sampling Efficiency Comparison
Sampling efficiency of the impactors was gravimetrically evaluated for total PM2.5 as well as for individual impaction stages, as appropriate, by sampling a test aerosol generated in a large environmental chamber. The test conditions for the sampling efficiency test were, although optimal for obtaining gravimetrically measurable levels of particles on all stages of the Sioutas PCIS, were several orders of magnitude higher than those experienced in most real-world settings. These aerosol concentrations caused the PEM pumps to operate at backpressures that were greater than the manufacturer’s specifications, although the pump logs did not report any pump failure.
Because the upper particle loading limit is a complex function of the ambient particle size distribution and type, humidity, individual filter used, capacity of the sampler flow rate control system, and possibly other parameters, it is not known whether these high concentrations resulted in particle bounce and/or affected the cutpoints of the particles collected for the DCI-6 and PEM reference samplers. The humidity in the environmental chamber did not exceed 29% and the temperature did not increase by more than 1.7°C during the one hour sampling period. The particle loadings did not exceed the manufacturer’s operating specifications for the maximum particle load per stage for the Sioutas PCIS, 3.16 mg/stage, nor did they exceed the federally mandated capability of the FRM, 4.8 mg PM2.5/filter. These particle loadings resulted in backpressures greater than those recommended for the Leland Legacy® pump. However, the samplers performed consistently, as the inter-sampler variability for all samplers in each of the three tests did not exceed 11% for the FRMs, 4% for the PEMs, 15% for the DCI-6, and 10% for the PCISs for each cutpoint in which the gravimetric masses were above three times the method detection limit.
Sampling Metals in Ambient Air
The ability of the PCIS to sample PM2.5 with detectable levels of metals/elements in ambient air was evaluated in comparison to reference PEM samplers for a 48-hour sampling period. Seven of the 38 metals/elements analyzed using XRF showed detectable levels in the PM2.5 collected. The dataset of S, Cl, Si, Ca, Fe, K and Zn results falls along a line that is significantly statistically different from the unity line, although the y-intercept,-0.54, is not significantly different from zero. The majority of the data falls below the unity line indicating an overall negative bias, 36%, for the Sioutas PCIS results as compared to those obtained using the reference PEMs. This ambient air low concentration of metal/element result is similar to that found in the test aerosol high concentration of particulate result discussed in the sampling efficiency comparisons. At both concentration levels, sub-μg/m3 of metal/element versus mg/m3 of particulate, the Sioutas PCIS results show a negative bias compared to the data for the reference samplers.
Ease of Use, Reliability and Subject Acceptance/Compliance
Seven non-smoking subjects were recruited to wear the PCIS for a period of 48 hours and keep a simple time/activity diary. At the end of the sampling period, subjects completed a questionnaire to gather information about the pump’s ease of operation, reliability, and their acceptance of the device. The pumps were equipped with small, data-logging multidirectional accelerometers. Questionnaire responses showed that subjects felt strongly that the PCIS noise was too loud and that they did not like wearing the pump, however; the noise wasn’t loud enough to prevent them from thinking or talking on the phone while wearing the sampler. The sound level of a single pump operating at the manufacturer’s recommended pressure drop ranged from 48-64 dB, which is a level similar to normal conversational speech (~60 dB). Sound levels measured for all four pumps operating at the highest pressure drop 19 inch H2O never exceeded 72 dB, which is equivalent to the sound level of a typical household vacuum cleaner. Subjects also felt strongly that the sampler (Leland Legacy® pump and Sioutas PCIS combination) was easy to take on and off and plug into the wall to run on A/C power while they slept. Examination of the accelerometer and time/activity diary data showed that although all of the subjects said they followed the sampling protocol, only half of the subjects followed the sampling protocol, and the other half stopped wearing the pump roughly after the first 24 hours.
Progress Summary:The SAP reviewed the Draft Final Report (submitted in 2006), and gave their approval. The report has been revised as necessary, and formatted for printing. The report will be published by both EPA (this will be posted at http://www.epa.gov/etv/center/center1.html) and the NUATRC (http://www.sph.uth.tmc.edu/mleland/ 
). The NUATRC’s formatted report is undergoing final review by EPA. The expected printing date is the end of January 2008.
Publication of final report.
Supplemental Keywords:, Ecosystem Protection/Environmental Exposure & Risk, HUMAN HEALTH, Scientific Discipline, Health, RFA, PHYSICAL ASPECTS, Health Effects, Risk Assessments, Aquatic Ecosystems & Estuarine Research, Health Risk Assessment, Physical Processes, Aquatic Ecosystem, Biochemistry, Genetics, water quality, urban environment, airborne urban contaminants, environmental tobacco smoke, respiratory disease, ozone, human health risk, air pollution, airway disease, particulate matter, exposure, allergic airway disease, asthma, human exposure
Progress and Final Reports:
2005 Progress Report
Original Abstract
Main Center Abstract and Reports:
R824834 Mickey Leland National Urban Air Toxics Research Center (NUATRC)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R824834C001 Air Toxics Exposures Among Teenagers in New York City and Los Angeles - A Columbia-Harvard Study (TEACH)
R824834C002 Cardiopulmonary Response to Particulate Exposure
R824834C003 VOC Exposure in an Industry Impacted Community
R824834C004 A Study of Personal Exposure to Air Toxics Among a Subset of the Residential U.S. Population (VOC Project)
R824834C005 Methods Development Project for a Study of Personal Exposures to Toxic Air Pollutants
R824834C006 Relationship Between Indoor, Outdoor and Personal Air (RIOPA)
R824834C007 Development of the "Leland Legacy" Air Sampling Pump
R824834C008 Source Apportionment of Indoor Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Residences
R824834C009 Development of a Personal Cascade Impactor Sampler (PCIS)
R824834C010 Testing the Metals Hypothesis in Spokane
R828678C001 Air Toxics Exposures Among Teenagers in New York City and Los Angeles—A Columbia-Harvard Study (TEACH)
R828678C002 Cardiopulmonary Effects of Metal-Containing Particulate Exposure
R828678C003 VOC Exposure in an Industry Impacted Community
R828678C004 A Study of Personal Exposure to Air Toxics Among a Subset of the Residential U.S. Population (VOC Project)
R828678C005 Oxygenated Urban Air Toxics and Asthma Variability in Middle School Children: A Panel Study (ATAC–Air Toxics and Asthma in Children)
R828678C006 Relationship between Indoor, Outdoor and Personal Air (RIOPA). Part II: Analyses of Concentrations of Particulate Matter Species
R828678C007 Development of the “Leland Legacy” Air Sampling Pump
R828678C008 Source Apportionment of Indoor PAHs in Urban Residences 98-03B
R828678C009 Development of a Personal Cascade Impactor Sampler (PCIS)
R828678C010 Testing the Metals Hypothesis in Spokane
R828678C011 A Pilot Geospatial Analysis of Exposure to Air Pollutants (with Special Attention to Air Toxics) and Hospital Admissions in Harris County, Texas
R828678C012 Impact of Exposure to Urban Air Toxics on Asthma Utilization for the Pediatric Medicaid Population in Dearborn, Michigan
R828678C013 Field Validation of the Sioutas Sampler and Leland Legacy Pump – Joint Project with EPA’s Environmental Technology Validation Program (ETV)
R828678C014 Performance Evaluation of the 3M Charcoal Vapor Monitor for Monitor Low Ambient Concentrations of VOCs
R828678C015 RIOPA Database Development
R828678C016 Contributions of Outdoor PM Sources to Indoor and Personal Exposures: Analysis of PM Species Concentrations” Focused on the PM Speciation and Apportioning of Sources
R828678C017 The Short and Long-Term Respiratory Effects of Exposure to PAHs from Traffic in a Cohort of Asthmatic Children