Sources, Chemical Components, and Toxicological Responses of Size Segregated Urban Air PM Samples in High Air Pollution Season in Guangzhou, China.

The sources, sizes, components, and toxicological responses of particulate matter (PM) have demonstrated remarkable spatiotemporal variability. However, associations between components, sources, and toxicological effects in different-sized PM remain unclear. The purposes of this study were to 1) determine the sources of PM chemical components, 2) in-vestigate the associations between components and toxicology of PM from Guangzhou high air pollution season. We col-lected size-segregated PM samples (PM10-2.5, PM2.5-1, PM1-0.2, PM0.2) from December 2017 to March 2018 in Guangzhou. PM sources and components were analyzed. RAW264.7 mouse macrophages were treated with PM samples for 24 h followed by measurements of toxicological responses. The concentrations of PM10-2.5 and PM1-0.2 were rela-tively high in all samples. Water-soluble ions and PAHs were more abundant in smaller-diameter PM, while metallic el-ements were more enriched in larger-diameter PM. Traffc exhaust, soil dust, and biomass burning/petrochemical were the most important sources of PAHs, metals and ions, respectively. The main contributions to PM were soil dust, coal combustion, and biomass burning/petrochemical. Exposure to PM10-2.5 induced the most signifcant reduction of cell mitochondrial activity, oxidative stress and inflammatory response, whereas DNA damage, an increase of Sub G1/G0 population, and impaired cell membrane integrity were most evident with PM1-0.2 exposure. There were moderate or strong correlations between most single chemicals and almost all toxicological endpoints as well as between various tox-icological outcomes. Our fndings highlight those various size-segregated PM-induced toxicological effects in cells, and identify chemical components and sources of PM that play the key role in adverse intracellular responses. Although fne and ultrafne PM have attracted much attention, the inflammatory damage caused by coarse PM cannot be ignored.