Role of Diesel and Other Vehicular Exhaust in Exacerbation of Childhood Asthma

Principal Investigator

Thomas Robins

Co-Principal Investigators

Stuart Batterman, Bhramar Mukherjee, Barbara Israel, Anna Michalak

Funding Sources

NIEHS

About this Project

The burden of childhood asthma disproportionately affects children living in poverty and in urban centers, many of whom are minority ethnic groups. For those living in urban environments with high traffic densities, there is increasing concern about potential adverse respiratory health effects of exposure to diesel and other vehicular exhaust. Epidemiologic studies have shown associations between exposure to high traffic volumes, and especially to high truck traffic -- the main source of diesel exhaust in urban settings -- and increases in asthma symptoms, asthma hospitalizations, and decreased lung function. Yet, owing to the challenges of separating diesel from spark ignition exhaust, and vehicular exhaust in general from other sources of pollution, quantitative associations between exposure to diesel and other vehicular exhaust and adverse respiratory health outcomes have not been well-characterized. This study is characterizing ambient exposures related to vehicular exhaust and other specific air pollutant sources, and evaluating the relationship of these exposures to the exacerbation of asthma among children living in Detroit and Dearborn, Michigan. We are collecting ambient and indoor household air quality data which provides both high temporal and spatial resolution of pollution concentrations and utilize state-of-the-art statistical/geospatial models to apportion exposures among pollutant sources including diesel and other vehicular exhaust and to develop individual-specific exposure estimates. We are conducting a two-year longitudinal study involving 210 asthmatic children with 70 each living near high traffic/high truck volume roads, near high traffic/low truck volume roads, and distant from high traffic roads. Daily health measures to be assessed for two consecutive weeks in each of eight seasons include respiratory symptoms, pulmonary function assessed by hand-held spirometer, medication use, and health services utilization. We hypothesize that: 1) exposures specific to diesel and other vehicular exhaust will be stronger predictors of adverse health status among children with asthma living in a high traffic density urban environment than other pollutant sources, and, 2) the presence of cigarette smokers in the household, or high levels of common allergens in household dust, will yield stronger exposure-response relationships between diesel and other vehicular exhaust and adverse respiratory health outcomes.

Studies in urban areas have found large increases in PM and components of PM specific to diesel truck exhaust measured in schools and homes located along and near highways.