Analysis of PM2.5 Inorganic and Organic Constituents to Resolve Contributing Sources in Seoul, South Korea and Beijing, China and Their Possible Associations With Cytokine Il-8

JIEUN PARK, Kyoung-Hee Lee, Hyewon Kim, Jisu Woo, Jongbae Heo, Kwon Ho Jeon, Chang-Hoon Lee, Chul-Gyu Yoo, Philip K. Hopke, Petros Koutrakis, Seung-Muk Yi, Harvard T.H. Chan School of Public Health

     Abstract Number: 724
     Working Group: Aerosol Exposure

Abstract
The most polluted countries in East Asia, namely South Korea and China, have large populations. As neighboring countries, collaborative management plans to maximize public health in both countries can be helpful in reducing transboundary air pollution. To support such planning, PM_2.5 inorganic and organic species were determined in simultaneously collected PM_2.5 integrated filters. The resulting data were used as inputs to positive matrix factorization, which identified nine sources at the ambient air monitoring sites in both sites. Secondary nitrate, secondary sulfate/oil combustion, soil, mobile, incinerator, biomass burning, and secondary organic carbon (SOC) were found to be sources at both sampling sites. Industry I and II were only identified in Seoul, whereas combustion and road dust sources were only identified in Beijing. A subset of samples was selected for exposure assessment. The expression levels of IL-8 were significantly higher in Beijing (167.7 pg/mL) than in Seoul (72.7 pg/mL). The associations between the PM_2.5 chemical constituents and its contributing sources with PM_2.5-induced inflammatory cytokine (interleukin-8, IL-8) levels in human bronchial epithelial cells were investigated. For Seoul, the soil followed by the secondary nitrate and the biomass burning showed increase with IL-8 production. However, for the Beijing, the secondary nitrate exhibited the highest association with IL-8 production and SOC and biomass burning showed modest increase with IL-8. As one of the highest contributing sources in both cities, secondary nitrate showed an association with IL-8 production. The biomass burning at both locations contained PAHs such as chrysene and indeno[1,2,3-cd]pyrene that are probable human carcinogens and showed modest association with IL-8 production. The soil source having the strongest association with IL-8 production was found only for Seoul, whereas SOC showed a modest association only for Beijing. This study can provide the scientific basis for identifying the sources to be prioritized for control to provide effective mitigation of particulate air pollution in each city and thereby improve public health.