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Modeling exposures to traffic-related air pollutants for the NEXUS respiratory health study of asthmatic children in Detroit, MI
Citation:
Burke, J., V. Isakov, M. Breen, AND S. Batterman. Modeling exposures to traffic-related air pollutants for the NEXUS respiratory health study of asthmatic children in Detroit, MI. ISES 2015 Annual Meeting, Henderson, NV, October 18 - 22, 2015.
Impact/Purpose:
The National Exposure Research Laboratory (NERL) Atmospheric Modeling and Analysis Division (AMAD) conducts research in support of EPA mission to protect human health and the environment. AMAD research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
The Near-Road EXposures and Effects of Urban Air Pollutants Study (NEXUS) was designed to investigate associations between exposure to traffic-related air pollution and the respiratory health of asthmatic children living near major roadways in Detroit, MI. A combination of modeling approaches were used to estimate exposures to traffic-related air pollutants for the NEXUS participants that varied both spatially and temporally for examining relationships with the health outcomes. Field studies were conducted to provide measurement data for developing, evaluating and refining the models. A new air pollutant dispersion model was developed to capture near-road spatial gradients of traffic-related air pollutants and incorporated into a hybrid modeling approach using detailed road network locations and traffic activity, local emission source information, meteorological data, and estimates of the regional background. Exposure modeling was also conducted to estimate daily residential air exchange rates for each home based on building characteristics, local temperatures and wind speeds. Daily exposure estimates were produced for multiple air pollutants at each NEXUS participant home and school location for the two year study period using the hybrid modeling approach, and showed similar spatio-temporal patterns compared to measurements. The modeled exposure estimates were also shown to better characterize exposure variability compared to simpler exposure metrics such as traffic intensity and distance to roads. The exposure model for estimating residential air exchange rates was calibrated and evaluated using measurements, and the daily air exchange rate estimates varied significantly between homes, with both daily and seasonal variations, which may account for differences in exposures across participants. The NEXUS results provide demonstration of an integrated measurement and modeling study design for air pollution health studies utilizing advanced modeling approaches
