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2004 Progress Report: The Role of Quinones, Aldehydes, Polycyclic Aromatic Hydrocarbons, and other Atmospheric Transformation Products on Chronic Health Effects in Children
EPA Grant Number: R827352C009Subproject: this is subproject number 009 , established and managed by the Center Director under grant R827352
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Southern California Particle Center and Supersite
Center Director: Froines, John R.
Title: The Role of Quinones, Aldehydes, Polycyclic Aromatic Hydrocarbons, and other Atmospheric Transformation Products on Chronic Health Effects in Children
Investigators: Avol, Edward L. , Cho, Arthur K. , Froines, John R. , Miguel, Antonio
Institution: University of Southern California , University of California - Los Angeles
Current Institution: University of California - Los Angeles , University of Southern California
EPA Project Officer: Stacey Katz/Gail Robarge,
Project Period: June 1, 1999 through May 31, 2005 (Extended to May 31, 2006)
Project Period Covered by this Report: June 1, 2003 through May 31, 2004
RFA: Airborne Particulate Matter (PM) Centers (1999)
Research Category: Particulate Matter
Description:
Objective:The overall purpose of this project is to provide exposure data on ambient organic pollutants in 12 communities participating in a long-term study of children’s respiratory health. Two specific objectives were identified for this project: (1) characterize the annual levels and seasonal variability of selected PAHs, aldehydes, and quinones in ambient air in the study communities; (2) apply the resulting data to ongoing analyses of health and ambient pollution exposure, to help disentangle a previously identified and highly inter-correlated package of pollutants associated with decrements in human health. See Table 1 for a list of target analytes.
Background: In 1993, a multi-year study of public school children (the California Children’s Health Study—CHS) was established in Southern California to assess the potential chronic health effects of ambient air pollution (Peters, et al., 1999). Twelve CHS communities were identified for study participation, based on their historic and predicted air pollution profiles, community demographics, and school district support. Over 6,000 4th, 7th, and 10th grade students were recruited, enrolled, and annually evaluated across these communities, to assess annual lung function growth, respiratory symptoms, and school-based absences caused by respiratory infection. To characterize local air quality, existing community air monitoring stations in each of the 12 communities were augmented with additional air sampling instrumentation, or a central air monitoring station was established, to provide continuous long-term information about ambient ozone, oxides of nitrogen, and particle concentration (as PM10 or PM2.5 mass), as well as particle speciation (PM2.5 acids, sulfates, nitrates, ammonium, elemental and organic carbon). Several health-based manuscripts have reported on the observed associations between specific pollutants, or inter- correlated groups of pollutants, and various health outcomes measured in the CHS (Gauderman, et al., 2000 ; Gauderman, et al., 2004 ; McConnell, et al., 1999 ; Gilliland, et al., 2001 ; Avol, et al., 2001 ; McConnell, et al., 2002).
However, the co-linear behavior of several monitored pollutants has made it difficult for investigators to assess the relative importance of single pollutant measures with observed health outcomes. In developing this component of the Southern California Particle Center’s research program, it was hoped that measurement of specific organic compounds could provide alternative exposure metrics, less complicated by collinearity. In addition, the study was designed to provide information regarding the inter-community variability of organic pollutants of potential health importance, such as polycyclic aromatic hydrocarbons (PAHs), primary and secondary aldehydes, and quinones, all of which are associated with the current urban living environment and motor vehicle emissions.
Progress Summary:Using an innovative sampler deployment approach to collect seasonal samples in 12 sampling locations with only three sets of instrumentation, field sampling was successfully performed in consecutive two-month deployments across all 12 CHS communities between 2001 and 2003. In the course of field operations, an improved sampling matrix was developed to successfully capture and stabilize particle and vapor-phase PAHs, aldehydes, and quinones in a multiple-media sampling matrix for 24-hr sampling intervals.
The collected samples were analyzed, edited, and developed into a cumulative database. Analyses were performed by both environmental researchers interested in the chemical interaction of pollutants in ambient air and by health researchers seeking to potentially disentangle previous associations among assorted respiratory health outcomes and a highly inter-correlated bundle of pollutants arising from energy combustion and vehicle emissions.
Achievements in Respect to Project Purpose and Objectives
The collected data have been invaluable with regard to achievement of the exposure characterization objective. This work has produced a rich database on exposure to a set of organic compounds found in the ambient air of 12 Los Angeles area communities. As a result of this study, enhanced appreciation of the interplay among ambient temperature, re-distribution of chemical species between gas and particle phases, and air toxics emissions associated with vehicle exhaust, energy combustion, and photochemistry have been afforded. Three manuscripts have been prepared documenting and describing these issues (Eiguren-Fernandez, et al., 2004 ; Eiguren-Fernandez, et al., 2005 ; Cho, et al., 2004).
The project’s second objective, to apply this data to health analyses to potentially de-couple previously observed relationships between a number of co-linear pollutants and respiratory health outcomes has also been achieved. Some associations between the target analytes and two key respiratory health effect measures have been observed. However, the analyses performed to date have not identified pollutants that provide significant explanatory power beyond that of routinely monitored substances (such as ambient NO2, PM2.5 mass, elemental carbon, and acids). While the exposure data provide limited additional information for the selected outcome measures, there are other health outcomes (such as disease status for asthma, susceptibility to bronchitis or pneumonias, and exacerbation of symptoms) that are being investigated.
Therefore, the research objectives of this project have, in large part, been fully realized. The information collected suggests several additional lines of inquiry and future analyses.
Details of all Significant Technical Aspects of the Project (Both Positive and Negative)
Methods. Three sets of sampling instrumentation were purchased or assembled for field study applications, in conformance with the project proposal. Samplers were initially evaluated in a multi-day side-by-side comparison in Los Angeles to assure comparability. Samplers were deployed, for alternating two-month periods beginning in mid-2001 and continuing into Fall 2003. Sampling was performed in three CHS communities at a time, with collection beginning at midnight for a 24-hour continuous period once every eight days. Upon completion of seven sampling days (about two months’ elapsed time), samplers were relocated to a second set of three study communities. There, sampling was performed in analogous fashion (e.g., the one-in-eight-day schedule), after which the samplers are re-calibrated and returned to the former three sampling sites for a repetition of the one-in-eight-day, two-month sampling protocol. In this manner, the three sets of samplers were used to collect speciated chemical data across six sampling sites each year, and data was collected at all 12 sampling locations over a two-year sampling period.
In each sampling location, two types of samplers were deployed: A Tisch Environmental Model 1202 Semi-Volatile Organic Compound (SVOC) and PM2.5 sampling system, and an in-house carbonyls sampler. PAH sampling was performed using a quartz filter/PUF/XAD resin sampling matrix, while carbonyl sampling was accomplished utilizing a more conventional DNPH-based sampling cartridge. Additional sampling details have been reported (Eiguren-Fernandez, et al., 2004 ; Cho, et al., 2004). Impurities in the PUF portion of the original sampling matrix led to persistent difficulties in laboratory quinone derivatization procedures. To avoid these problems, a revised sampling matrix that included additional XAD resin was utilized in the second year of sampling (i.e., in the second six CHS communities—Long Beach, Lancaster, Santa Maria, Lake Elsinore, Alpine, and Lake Arrowhead). This change dramatically improved the ability to quantify vapor-phase quinones. A few of the targeted collection species’ data (anthroquinone and acrolein) had to be invalidated, due to concerns about collection validity and artifact formation on the collection media.
Existing community monitoring stations provided supporting air monitoring information for several other pollutants of analytical interest (ozone [O3], nitrogen dioxide [NO2], PM mass [PM10 and PM2.5], elemental carbon [EC], organic carbon [OC], and nitric/formic/acetic acids [acid]). Data from the routine sites were used to derive a 1994 through 2003 average level for pollutants of interest, and to develop a 2001 through 2003 concentration metric. The 1994- 2003 averages were used to compare the relative health outcomes from analyses with those observed in a recent publication of CHS data (Gauderman, et al., 2004). The 2001- 2003 calculations were used to provide a sampling interval more specifically appropriate to the time-frame of the PAH, carbonyl, and quinone measurements collected in the current study.
Health outcome data used in the analyses included indices of changes in two lung function tests: forced expiratory volumes in the first second of exhalation (FEV1) and the maximal mid-expiratory flow rate (MMEF). Changes in FEV1 or MMEF have been previously shown to be significantly affected by air pollution in this schoolchildren population, and are thought to represent changes in large and small airways, respectively (Gauderman, et al., 2004 ; Gauderman, et al., 2000 ; Avol, et al., 2001). To qualitatively compare present analyses with those previous published results of long-term growth, only those subjects who entered the CHS as 4th graders (i.e., those whose lung function growth was tracked annually for the duration of the multiple-year CHS study) were included in the health analyses.
Data Analyses Performed. Following editing and validation of the sampling data set, several analytical approaches were applied. For exposure assessment analyses, individual pollutant means, medians, and minimum/maximum values were tabulated by community and in total to assess summary distributions and consider possible correlations across the various pollutant metrics. Correlation tables were developed for all validated pollutants and the 1994-2003 and 2001-2003 pollution metrics available from the CHS to identify possible unique contributors to observed health outcomes. One and two-pollutant models were then used to explore the possible additional explanatory value contributed by PAHs, carbonyls, or quinones over that provided by the previously available study pollutants in analyses of lung function endpoints.
A multi-stage modeling strategy was used to assess the relationship of PAHs, aldehydes and quinones to lung function measurements from children residing in the study communities and participating in a long-term health study (Gauderman, et al., 2004).
The first-stage model was a linear regression of each lung function measure (logtransformed) on log height, body mass index (BMI), BMI2, race, Hispanic ethnicity, doctor-diagnosed asthma, any tobacco smoking by the child in the last year, exercise or respiratory illness on the day of the test, and indicator variables for field technician and spirometer.
The second stage consisted of a regression of 48 (2 cohorts × 2 sexes × 12 communities) estimates of lung function growth over the eight-year period on the corresponding mean/median level of PAHs, aldehydes, and quinones in each community. The inverses of the first-stage variances were used as weights, and a community-specific random effect was included to account for residual variation between communities. Modification of the PAH effect by cohort was tested by including a cohort-by-PAH/aldehyde/quinone interaction term. This effect was found to be non-significant and hence all subsequent analyses were based on combined cohort effects. A similar procedure was followed to test for modification effect of PAH by sex. All subsequent models were adjusted for both cohort and sex unless otherwise specified.
Two-pollutant models were also tested by simultaneously regressing growth in lung function over the eight-year period on pairs of pollutants, of which one pollutant was a routinely monitored pollutant such as ambient NO2, PM2.5 mass, elemental carbon, and acids and the other pollutant was one of the PAHs, aldehydes, or quinones measured in the current study.
Pollutant effect estimates were reported as the difference in lung function growth between the highest to the lowest pollution community, with negative sign denoting the detrimental effect with increasing exposure. Statistical procedures were performed using a commercially available statistical package (SAS, Version 9). Statistical significance was defined by a two-sided alpha level of 5%.
Selected Results–Pollutant Levels. In the collected samples with XAD backup, virtually all of the total PAH mass was contained in the vapor phase. Vapor phase PAH mass was dominated by naphthalene (NAP), which varied from about 60 ng/m3 in lightly-trafficked rural communities to over 550 ng/m3 in communities traversed by ~200,000 vehicles per day. During summer pollution episodes in urban sites, NAP concentrations reached 7 to 30 times the observed annual averages for those same locations.
Similar concentrations of particle-phase PAHs were observed at all sites except for one rural coastal site, which was markedly lower. Benzo[ghi]perylene (BGP), a marker of gasoline exhaust emissions, showed the highest concentration among particle-phase PAHs, varying from 23 pg/m3 in rural areas to over 230 pg/m3 in communities containing high volumes of freeway traffic (hundreds of thousands of vehicles per day). Benzo[a]pyrene and indeno[1,2,3-cd]pyrene were found exclusively in the particle-phase, and they were much higher in urban sites (~ 40 to 100 pg/m3) than in rural sites (~12 pg/m3). Winter particle-phase PAHs were 2 to 54 times higher than summer levels. The data suggest that vehicle emissions are a major contributor to particle-phase PAHs in Southern California.
Except for summer episodes, concentrations of the low MW PAHs showed small seasonal variations, with observed values about twice as high in winter. Cold/hot season ratios for PAHs in PM2.5 averaged 5.7, with a maximum ratio of 54 calculated for data collected in Long Beach, a coastal community impacted by significant levels of primary emissions from vehicle traffic, commercial shipping, oil refineries, and population activities. Particle-phase PAHs were negatively correlated with mean air temperature in urban sites (r = -0.50 to -0.75). These data underscore the importance of seasonal variation in atmospheric metrics such as ambient temperature, photochemical reactivity, and inversion layer height, as well as in gas-to-particle phase shifts of semi-volatile PAHs in ambient air.
Pollutant Correlations. Vapor-phase PAHs were essentially un-correlated with ambient ozone (as 24-hr, 10 am to 6 pm, or maximum value metrics), 24-hr NO2, 24-hr PM10, acids, elemental carbon (EC), or organic carbon (OC). Naphthalene was found to be moderately correlated with acids (r=0.643, p=0.02) and with NO2 (r=0.610, p=0.035). In contrast, there were a number of strong correlations between particulate PAHs and routinely measured pollutants, including pyrene and acids (r=0.896, p<0.0001), 24hr NO2 (r=0.797, p=0.002), and 24hr PM10 (r=0.707, p=0.01). Acenapthene (r=.769, p=0.003), fluorine (r=0.821, p=0.001), and naphthalene (r=.708, p=0.01) were highly correlated with 24hr O3, and fluoranthene was found to be highly collinear with 24hr NO2 (r=0.869, p=0.0002).
A number of aldehydes (formaldehyde, acetaldehyde, acetone, protonaldehyde, and butanone) were found to be very highly correlated with ambient acids, 24hr NO2, 24hr PM10, OC and EC, (coefficients of 0.7 to 0.9, and p-values typically less than 0.001).
Among the quinones monitored, particle-phase 1,4 naphthoquinones were strongly correlated with acids (r=0.782, p=.003), 24hr NO2 (r=0.627, p=0.029) and marginally correlated with EC (r=0.561, p=0.058) and 24hr PM10 (r=0.567, p=0.055). Particle-phase phenanthroquinones were found to be correlated with acids (r=0.630, p=0.028). No other particle or gas-phase quinones were correlated with routinely monitored pollutants.
Correlations and relationships between and among the routinely measured pollutants and target analytes of this study were similar when the 1994 through 2003 community pollution exposure averages or the 2001 through 2003 community pollution exposure averages were used. The latter were more specific to the current organic sampling study timeframe, but both provided similar and consistent results. This observation provides some validation for comparing PAH, aldehyde, and quinone exposures to the longitudinal health outcomes derived from the ten-year cumulative health investigations.
Health Analyses. Two-pollutant models comparing pollution level and lung function growth rate changes were run, to assess the relative importance of each individual organic pollutant monitored in the current study compared to the pollutant data set (i.e., O3, NO2, PM10, PM2.5, EC, OC, and acids) previously available from the health study communities.
Two-pollutant models with pollutants that have previously been linked to decrements in lung function growth rates showed a distinctly different pattern. In comparisons of NO2 with the PAHs, quinones, and aldehydes, NO2 was found to be significant in most every comparative case. In models with PM2.5 and each test PAH, quinone, or aldehyde measured, PM2.5 was found to be the more significant modeled pollutant in most every comparative case.
These results suggest that although some of the PAHs, quinones, and aldehydes measured in the study do appear to be associated with decrements in lung function growth, their added explanatory power is limited, compared to the decrements already identified by associations with the inter-correlated package of pollutants previously monitored (including NO2, PM2.5, EC, and acids). This suggests that, with respect to lung function growth rate indices, the PAHs, quinones, and aldehydes measured may not disentangle the “package” of pollutants previously found to be associated with the lung function growth indices examined.
Data analysis on the data collected will continue, and additional results will be reported as they become available.
Conclusions
Ambient air samples were collected in 12 Southern California communities to assess seasonal variability and annual estimates of 15 PAHs, four quinones, and 15 aldehydes of environmental and health concern. Analyses revealed that:
- Virtually all of the total PAH mass was contained in the vapor phase, and vapor phase PAHs were dominated by naphthalene;
- Vapor-phase PAH concentrations were essentially uncorrelated with more commonly measured pollution components (O3, NO2, PM10, EC, OC, and ambient acids);
- Particle-phase PAH levels were similar across most sites ;
- Winter particle PAH levels were 2 to 54 times higher than summer levels; seasonal differences increased with greater molecular weight ;
- Particle-phase PAHs were negatively correlated with mean air temperature;
- Several particle-phase PAHs and aldehydes were strongly correlated with more commonly measured pollution components (O3, NO2, PM10, EC, OC, and ambient acids).
Table 1. Target Analytes of the Organics Sampling Study
PAHs |
Quinones |
Carbonyls |
Naphthalene (NAP) |
1,2-Naphthoquinone (1,2NQ) |
Formaldehyde (FOR) |
Acenaphthene (ACE) |
1,4-Naphthoquinone (1,4NQ) |
Acetaldehyde (ACD) |
Fluorene (FLU) |
9,10-Phenanthroquinone (PQ) |
Acetone (ACE) |
Phenanthrene (PHE) |
9,10-Anthroquinone (AQ) |
Acrolein (ACR) |
Anthracene (ANT) |
|
Propionaldehyde (PRO) |
Fluoranthene (FLT) |
|
Crotonaldehyde (CRO) |
Pyrene (PYR) |
|
Butanone (BUT) |
Benz[a]anthracene (BAA) |
|
Butyraldehyde (MET) |
Chrysene (CRY) |
|
Benzandehyde (BEN) |
Benzo[b]fluoranthene (BBF) |
|
Isovalerandehyde |
Benzo[k]fluoranthene (BKF) |
|
Valeraldehyde (VAL) |
Benzo[a]pyrene (BAP) |
|
o-tolualdehyde (OTO) |
Indeno[1,2,3-c,d]pyrene (IND) |
|
m-tolualdehyde (MTO) |
Dibenz[a,h]anthracene (DBA) |
|
p-tolualdehyde (PTO) |
Benzo[g,h,i]perylene (BGP) |
|
Hexaldehyde (HEX) |
References:
Avol EL, Gauderman WJ, Tan SM, London S, Peters JM. Respiratory effects of relocating to areas of differing air pollution levels. American Journal of Respiratory and Critical Care Medicine 2001;164:2067-2072.
Cho AK, Di Stefano E, You Y, Rodriguez CE, Schmitz DA, Kumagai Y, Miguel AH, Eiguren-Fernandez A, Kobayashi T, Avol E, Froines JR. Determination of four quinones in diesel exhaust particles SRM 1649a and atmospheric PM2.5. Aerosol Science & Technology 2004;38(S1):68-81.
Eiguren-Fernandez A, Miguel AH, Froines JR, Thurairatnam S, Avol EL. Seasonal and spatial variation of polycyclic aromatic hydrocarbons in vapor-phase and PM2.5 in Southern California urban and rural communities. Aerosol Science & Technology 2004;38:1-12.
Eiguren-Fernandez A, Avol EL, Thurairatnam S, Hakami M, Zhu Y, Froines JR, Miguel AH. Seasonal variation greatly influences particle-phase PAH concentrations in urban Southern California communities. Environmental Science & Technology (in review, 2005).
Gauderman WJ, McConnell R, Gilliland F, London S, Thomas D, Avol E, Vora H, Berhane K, Rappaport EB, Lurmann F, Margolis HG, Peters JM. Association between air pollution and lung function growth in Southern California children. American Journal of Respiratory and Critical Care Medicine 2000;162:1383-1890.
Gauderman WJ, Avol E, Gilliland F, Vora H, Thomas D, Berhane K, McConnell R, Kuenzli N, Lurmann F, Rappaport E, Margoli H, Bates D, Peters J. The effect of air pollution on lung function development in children aged 10 to 18 years. The New England Journal of Medicine 2004;351:1057-1067.
Gilliland FD, Berhane K, Rappaport EB, Thomas DC, Avol E, Gauderman J, London SJ, Margolis HG, McConnell R, Islam KT, Peters, JM. The effects of ambient air pollution on school absenteeism due to respiratory illnesses. Epidemiology 2001;12:43-54.
McConnell R, Berhane K, Gilliland F, London SJ, Vora H, Avol E, Gauderman WJ, Margolis HG, Lurmann F, Thomas DC, Peters JM. Air pollution and bronchitic symptoms in Southern California children with asthma. Environmental Health Perspectives 1999;107(9):757-760.
McConnell R, Berhane K, Gilliland F, Islam T, Gauderman WJ, Avol E, Margolis HG, Peters JM. Asthma in exercising children exposed to ozone: a cohort study. Lancet 2002;359(9304):386-391.
Peters JM, Avol EL, Navidi W, London SJ, Gauderman WJ, Lurmann F, Linn W, Margolis H, Rappaport E, Gong H. JR, Thomas D. A study of twelve Southern California communities with differing levels and types of air pollution. I. Prevalence of respiratory morbidity. American Journal of Respiratory and Critical Care Medicine 1999;159:760-767.
Journal Articles:No journal articles submitted with this report: View all 5 publications for this subproject
Supplemental Keywords:HUMAN HEALTH, Air, Geographic Area, Scientific Discipline, Health, RFA, Health Effects, Risk Assessments, Air Pollutants, Health Risk Assessment, particulate matter, Environmental Chemistry, Environmental Monitoring, mobile sources, State, aerosols, automotive exhaust, epidemiology, California (CA), engine exhaust, indoor air quality, allergens, particulate emissions, children's health, automobiles, human health effects, air pollution, atmospheric chemistry, children, automotive emissions, dosimetry, PAH, motor vehicle emissions, PM characteristics, ambient aerosol, asthma, human exposure
Relevant Websites:
Progress and Final Reports:
2001 Progress Report
2002 Progress Report
2003 Progress Report
Original Abstract
Final Report
Main Center Abstract and Reports:
R827352 Southern California Particle Center and Supersite
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R827352C001 The Chemical Toxicology of Particulate Matter
R827352C002 Pro-inflammatory and the Pro-oxidative Effects of Diesel Exhaust Particulate in Vivo and in Vitro
R827352C003 Measurement of the “Effective” Surface Area of Ultrafine and Accumulation Mode PM (Pilot Project)
R827352C004 Effect of Exposure to Freeways with Heavy Diesel Traffic and Gasoline Traffic on Asthma Mouse Model
R827352C005 Effects of Exposure to Fine and Ultrafine Concentrated Ambient Particles near a Heavily Trafficked Freeway in Geriatric Rats (Pilot Project)
R827352C006 Relationship Between Ultrafine Particle Size Distribution and Distance From Highways
R827352C007 Exposure to Vehicular Pollutants and Respiratory Health
R827352C008 Traffic Density and Human Reproductive Health
R827352C009 The Role of Quinones, Aldehydes, Polycyclic Aromatic Hydrocarbons, and other Atmospheric Transformation Products on Chronic Health Effects in Children
R827352C010 Novel Method for Measurement of Acrolein in Aerosols
R827352C011 Off-Line Sampling of Exhaled Nitric Oxide in Respiratory Health Surveys
R827352C012 Controlled Human Exposure Studies with Concentrated PM
R827352C013 Particle Size Distributions of Polycyclic Aromatic Hydrocarbons in the LAB
R827352C014 Physical and Chemical Characteristics of PM in the LAB (Source Receptor Study)
R827352C015 Exposure Assessment and Airshed Modeling Applications in Support of SCPC and CHS Projects
R827352C016 Particle Dosimetry
R827352C017 Conduct Research and Monitoring That Contributes to a Better Understanding of the Measurement, Sources, Size Distribution, Chemical Composition, Physical State, Spatial and Temporal Variability, and Health Effects of Suspended PM in the Los Angeles Basin (LAB)