2002 Progress Report: Traffic Density and Human Reproductive Health

EPA Grant Number: R827352C008
Subproject: this is subproject number 008 , 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: Traffic Density and Human Reproductive Health
Investigators: Ritz, Beate R.
Institution: University of California - Los Angeles , Michigan State University , University of California - Irvine , University of Southern California
Current Institution: University of California - Los Angeles
EPA Project Officer: Chung, Serena
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) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air


The overall 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—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 objective of this research project is to determine whether residential proximity to heavy traffic roadways, such as freeways and major arterials, affected the risk of low birth weight and preterm birth in infants born to women living in Los Angeles County, CA, between 1994-2000. Residential proximity to heavy traffic roadways is used as a surrogate measure of exposure to motor vehicle exhaust.

Progress Summary:

In previous work, we used a simple distance-weighted traffic density (DWTD) measure to assess exposure to motor vehicle exhaust. This research project recalculated the DWTD exposure measures for our birth cohort using methods that take meteorological and seasonal factors into account more adequately. We completed estimation of the DWTD parameters for our selected sample of 1994-1996 births, and these results were published in the February 2003 issue of Environmental Health Perspectives. Since mid-2002, we have made several refinements to this research. First, we used the Geographic Data Technologies Dynamap™ to geocode home locations; this map afforded us a better match rate of subjects' homes than maps used previously. Second, we expanded the analysis to include births from 1994-2000, which increased our sample size and allowed us to explore effect measure modification by factors such as maternal age or race, season, and proximity to freeways versus major arterials. Third, we created new traffic maps for calculation of the DWTD parameter. Additionally, we conducted a small measurement study to assess the accuracy of our DWTD measure in estimating indoor pollutant concentrations. We measured CO concentrations outside and inside of 56 homes located in four communities in Los Angeles County for 48-hour periods (CO was considered a marker for motor vehicle exhaust). The 48-hour average CO concentrations then were compared to the DWTD values calculated for each home. We found that correlations between 48-hour indoor and outdoor CO concentrations and DWTD values increased when the percent of time that a residence was downwind of a given street and incorporated into the measure.

Future Activities:

We will recalculate the DWTD exposure measures for our birth cohort using methods that take meteorological and seasonal factors into account more adequately. We will complete a meteorological model (the MM5 model) to obtain data on wind direction, wind speed, and inversion layer height for each subject in our sample. We also will use meteorological data recorded at the South Coast Air Quality Management District’s monitoring stations for comparison to the MM5 output. These meteorological data will be used to adjust DWTD values that we have calculated for our sample of 1994-2000 births. Logistic regressions will be used to evaluate the relationship between DWTD (as a proxy measure of exposure to motor vehicle exhaust) and low birth weight and premature birth. We will perform such analyses using both the simple DWTD values (i.e., not taking meteorological factors into account) and the refined DWTD values (that incorporate meteorological information) to determine whether additional consideration of factors such as wind direction, wind speed, and inversion layer height improve exposure estimates and change resulting health effect estimates.

Journal Articles:

No journal articles submitted with this report: View all 2 publications for this subproject

Supplemental Keywords:

Particulate matter, quinones, PAHs, aldehydes, ketones, human health risk, freeway study, California, mobile sources, motor vehicle emissions, residential proximity, indoor air quality, low birth weight, distance weighted traffic density,, RFA, Scientific Discipline, Air, Geographic Area, HUMAN HEALTH, particulate matter, Environmental Chemistry, Health Risk Assessment, Air Pollutants, State, mobile sources, Health Effects, Environmental Monitoring, engine exhaust, ambient aerosol, asthma, motor vehicle emissions, epidemiology, human health effects, quinones, automotive emissions, particulate emissions, automobiles, automotive exhaust, air pollution, children, PAH, human exposure, PM characteristics, California (CA), allergens, indoor air quality, aerosols, atmospheric chemistry

Relevant Websites:

http://www.scpcs.ucla.edu/ exit EPA

Progress and Final Reports:

Original Abstract
  • 1999
  • 2000
  • 2001 Progress Report
  • 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)