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Spatiotemporal Distribution and Source Apportionment of Macrophage Reactive Oxygen Species Activity of Ambient Fine Particulate Matter (PM2.5) in the Midwestern United States
YIXIANG WANG, Haoran Yu, Joseph V Puthussery, Sudheer Salana, Vishal Verma, University of Illinois Urbana-Champaign
Abstract Number: 114
Working Group: Health-Related Aerosols
Abstract
Ambient fine particulate matter (PM2.5) causes millions of premature mortalities every year. To better monitor the air quality, the capability of the particles to generate reactive oxygen species (ROS), conveniently called the ROS activity is a promising air quality indicator that is linked to the PM2.5 toxicity. However, very limited studies had investigated the spatial and temporal distribution of ROS activity in a large geographical area. Moreover, most of those researches assessed the ROS activity using the chemical assays, which do not necessarily represent the cellular responses. To understand the spatial and seasonal distribution of the cellular ROS activity of ambient PM2.5 in the Midwestern United States, we collected a large number of ambient PM2.5 samples (N= 237) from five sites in and around Illinois: Bondville (IL), Chicago (IL), Champaign (IL), Indianapolis (IN), and St. Louis (MI) for one complete year. Cellular ROS activity was measured by exposing the rat macrophage cells to the PM2.5 water extract. Chemical compositions of the PM2.5 samples were also analyzed by measuring the concentration of elemental and organic carbon, water-soluble organic carbon, water-soluble metals, and inorganic ions. The correlation between cellular ROS and chemical composition indicates that transition metals (Cu, Fe, and Mn), and water-soluble organic carbon were highly correlated with the macrophage ROS activity. The spatial distribution of macrophage ROS shows a strong intercorrelation among all the sites. Despite being in a rural area impacted only by the agricultural emissions, the Bondville site showed the second-highest macrophage ROS activity. This highlights the importance of agricultural emissions on contributing to the health impacts associated with ambient PM2.5. The source apportionment analysis is currently underway, which will reveal the emission sources contributing to the PM2.5 oxidative stress in the Midwestern United States.