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2002 Progress Report: Exposure to Vehicular Pollutants and Respiratory Health
EPA Grant Number: R827352C007Subproject: this is subproject number 007 , 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: Exposure to Vehicular Pollutants and Respiratory Health
Investigators: McConnell, Rob , Avol, Edward L. , Gauderman, William , Gilliland, Frank , Lurmann, Fred , Peters, John M.
Current Investigators: McConnell, Rob , Avol, Edward L. , Gauderman, William , Lurmann, Fred
Institution: University of Southern California , Michigan State University , University of California - Irvine , University of California - Los Angeles
Current Institution: Sonoma Technology, Inc. , 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, 2001 through May 31, 2002
RFA: Airborne Particulate Matter (PM) Centers (1999)
Research Category: Particulate Matter
Description:
Objective:The objective of this research project is to focus on the central hypothesis of the Southern California Particle Center and Supersite, which is that organic constituents associated with particulate matter (PM)—including quinones, other organic compounds (polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and aldehydes/ketones), and metals—are capable of generating reactive oxygen species and acting as electrophilic agents. They have a central role in allergic airway disease such as asthma and cardiovascular effects through their ability to generate oxidative stress, inflammation, and immunomodulating effects in the lungs and airways.
The specific objectives of this research project are to: (1) examine the association of the proximity of residences and schools to heavy traffic corridors with lung function, lung function growth, and asthma prevalence and incidence in children; and (2) enhance, refine, and evaluate mobile source emissions modeling techniques that are used to characterize the exposure of participants to mobile source emissions.
Progress Summary:Effect of Traffic on Asthma Prevalence. In analyses using early modeled home exposures, there was an increased risk of lifetime asthma (OR 7.0; 95 percent confidence interval 2.7-29) for the top decile of traffic-related exposure among children living at the same address since age 2 (McConnell, 2002). Within Long Beach (the highest traffic community), we observed an increasing risk of prevalent asthma across the gradient of traffic in this community. In a sample of 287 homes selected to represent the extremes of traffic exposure in our communities, we obtained 2-week measurements of NO2 during summer and winter seasons. Despite the small sample size, a significant association was observed between average NO2 at homes and a history of asthma at study entry (relative risk 2.5/10 ppb NO2; 95 percent confidence interval 1.04; 5.9). When we restricted the analysis to 45 lifetime residents, the relative risk increased to 11, albeit with wide confidence intervals (1.1, 60), because of an even smaller sample size. We currently are preparing a manuscript based on these results.
We also are using recent, better exposure information from Fred Lurmann, based on more accurately geo-coded roadways, to reexamine associations with modeled exposures seen in earlier years. In these analyses, in addition to the (somewhat weaker) effects of exposures in the top decile previously observed with Fred Lurmann's older models, we have observed associations with distance from a freeway for the first time. Modeled exposure from freeways and residential distance to a freeway both suggest that asthma risk increases as one gets closer to freeway traffic. We are finalizing these analyses, and we will prepare a manuscript for submission in Year 5 of the project.
Effect of Traffic on Lung Function and Lung Function Growth. We observed significant negative associations between the levels of forced expiratory volume-1, forced vital capacity, and maximum midexpiratory flow at the time of entry into the study and traffic-modeled pollutants generated by Fred Lurmann. The effects were, in general, slightly larger in children who always had lived at the same address. For lung function growth, there was no effect of modeled residential traffic-related pollutant exposure over the course of the study in the entire population. When the analysis was restricted to children who had lived their entire lives at the same address, however, there were suggestive negative associations between the growth of both volume and flow rates and traffic. One interpretation is that there is an early life effect of traffic exposure on lung function, which also predisposes children to later childhood effects of traffic on lung function growth. We plan to finalize these analyses in Year 5 of the project.
New Approaches to Examining Within-Community Variability in Pollutant Exposures. In a new approach to evaluating within-community variability in pollutant exposure, we have examined the effect of year-to-year variation in the average ambient pollutants measured at the central monitoring sites within each community. To our knowledge, the effect of organic carbon (OC) has not been examined previously in population-based health studies of chronic symptoms, and the approach to examining yearly variations in pollution has not been used previously. Two findings were of interest: (1) PM2.5, of the PM constituents, and OC were the pollutants that showed the most consistently significant effect in two pollutant models examining the effect of year-to-year variation within communities, a finding which is consistent with the results of animal and in vitro experimental studies at the Center; and (2) the within-community effect over time was threefold to fourfold larger (per unit of pollutant) than the between-community effect, suggesting that previous cross-sectional comparisons between communities may underestimate the true effect of air pollution, at least for the index of asthma severity we have examined (McConnell, 2002a). We observed that the effect of pollutants measured was significantly larger among children playing team sports, who ventilate their lungs more during periods of high concentrations of photochemical-oxidant pollutants, and therefore may receive larger doses of pollutants. These results may have important regulatory implications. This analysis has been completed, and a manuscript is in review.
Future Activities:We will publish the results of these analyses in Year 5 of the project. We plan to prepare manuscripts that focus on the following subjects:
- The relationship of distance to freeway and traffic-modeled NO and PM2.5 on lifetime risk of asthma in lifetime residents at the same address.
- The large risk of lifetime asthma associated with ambient NO2 at homes.
- The variation in bronchitis among asthmatic children associated with year-to-year variability in OC (in revision).
In addition to manuscript preparation, we will examine the effect of the distance and estimated time between home and school (in the data set developed at the Center by Arthur Winer and Jun Wu), in conjunction with existing information for our children on how they travel to and from school. Working with the modeling strategy, which assumes exceedingly rapid decay of pollutant effects around roadways (Brunekreef, 1997), Fred Lurmann has developed "traffic density" models for Long Beach that would reflect pollutant exposure that behaves in this way. Fred Lurmann has provided these models to us, and he will be developing these models for all study communities, which we will evaluate as predictors of health outcomes in Year 5 of the project.
For the assessment of health outcomes in Year 5 of the project, investigators also will examine how polymorphisms in genes coding for GSTM1 and GSTP1, enzymes involved in the pulmonary response to oxidant stress, may modify the effects of traffic-modeled exposure to pollutants within communities. We also will examine the relationship of traffic-modeled pollution with repeatedly measured 24-hour PM10 and ozone both at a central site monitor and at 90 homes in an existing data set in three Southern California communities. Fred Lurmann and Arthur Winer also will refine the analysis of the relationship between measured NO2 at homes and traffic-modeled NO2 by accounting for background contributions of NO2 and meteorologic factors at the time that NO2 was sampled.
Journal Articles:No journal articles submitted with this report: View all 7 publications for this subproject
Supplemental Keywords:Children's health, particulate matter, quinones, PAHs, aldehydes, ketones, metals, allergic airway disease, human health risk, asthma, mobile source emissions modeling, diesel exhaust particles, organic carbon, ultrafine particle concentration, California, freeway study, indoor air,
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HUMAN HEALTH, Air, Geographic Area, Scientific Discipline, RFA, Health Effects, 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, 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
Original Abstract
2003 Progress Report
2004 Progress Report
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)