AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Impacts of Emission Sources on Spatiotemporal Variability in Aerosol Oxidative Potential
JOSEPHINE BATES, Rodney J. Weber, Joseph Abrams, Vishal Verma, Ting Fang, Cesunica Ivey, Mitchel Klein, Matthew Strickland, Stefanie Ebelt Sarnat, Howard Chang, James Mulholland, Paige Tolbert, Armistead G. Russell, Georgia Institute of Technology
Abstract Number: 324 Working Group: Linking Aerosol Oxidative Potential with Chemical Composition and Biological Endpoints
Abstract Oxidative stress caused by the catalytic generation of reactive oxygen species induced by inhaled particulates is a suspected mechanism of aerosol toxicity. Oxidative potential, or ability to generation reactive oxygen species, of aerosols can vary spatially, temporally, and by composition. An acellular dithiothreitol (DTT) assay was used to measure the oxidative potential of ambient water-soluble PM2.5 at six sites (four urban and two rural) across the Southeastern United States from June 2012-July 2013. CMAQ-DDM was used to estimate 16 source impacts on ambient PM2.5 across the Eastern United States during the study time period. Ordinary least squares linear regression analyses with backward selection was used to relate particulate source impacts to water-soluble DTT activity, developing a model that estimates daily aerosol oxidative potential across the Eastern United States. This model was applied to daily estimates of CMAQ-DDM source impacts during the study time period to map spatial and seasonal patterns in oxidative potential of ambient aerosols. Spatial patterns show higher values in urban areas compared to rural areas, driven by the significant contribution of diesel vehicles to oxidative potential. Areas with fire activity also show aerosols with high oxidative potential, as supported by previous source apportionment work using the Chemical Mass Balance Method in Atlanta, GA. Overall, modelled oxidative potential is higher in the winter than the summer, which is supported by DTT assay measurements and the prevalence of prescribed burning in the winter in the Southeastern United States. Local source impacts affect the spatial and temporal distribution of aerosol oxidative potential, thus emphasizing the importance of understanding the association between source impacts and oxidative potential for both regulatory purposes and health studies.