10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Reactive Oxygen Species (ROS) Activity Map Induced by PM2.5 in 10 Different Cities, China
SHEXIA MA, Yanshan Lv, Xiaoying Li, Yangyang Zhang, Xuejun Liu, Mei Zheng, South China Institute of Environmental Sciences, MEP
Abstract Number: 63 Working Group: Aerosol Exposure
Abstract Numerous epidemiological studies have confirmed that exposure to ambient fine particulate matter (PM2.5) may increase cardiopulmonary mortality and morbidity. Oxidative potential (the ability of ambient particles to generate ROS) is a more relevant measurement when attempting to link aerosols and health end points. In this study, we quantify the oxidative potential of ambient particles collected during four seasons in 10 cities, China, using the dithiothreitol (DTT) assay, and aim to investigate the spatial and seasonal heterogeneity of ROS induced by PM2.5 in China. We find that PM2.5 are generally more reactive in clean days (<75μg/m3) than in polluted days (>75μg/m3), the increased health risk is gradually reduced per unit PM2.5 mass when PM2.5 concentration was above 75μg/m3. Annual average of blank-corrected DTT loss ranged from 1.42 to 25.50 pmol DTT min-1μg-1 PM among the 10 sites with a mean of 6.122±7.086 pmol DTT min-1μg-1 PM. The highest DTT activity was observed at the Guangzhou and the lowest occurred at the Baoding, with the ratio of average DTT loss is 5.25. The spatial distribution of DTT activity generated by PM2.5 collected in 10 different cities shows that higher DTT loss in coastal sites such as Guangzhou, Dalian, Fuzhou etc., lower DTT loss in inland sites, such as Baoding, Dezhou, Handan etc, which is the first spatial ROS activity map in China. There is a clear seasonal variation with highest activity in summer and lowest activity in spring, the average ratio of 1.97, indicated different sources and chemical properties of PM2.5 had significant effect on ROS generation. Slightly higher relative risks (RRs) of ambient PM2.5 were observed in Guangzhou and Dalian with lower PM2.5 level, while the lowest RRs were observed in Beijing with higher PM2.5, which was consistent with ROS activity map in the present study, suggesting that smaller particles, which might contain more toxins from anthropogenic emissions, can more easily reach the acinar part and promote oxidative stress and inflammation.