Fine particulate matter (e.g., PM2.5) can incorporate with toxic trace metals and other chemicals, posing high risks to human health. Due to rapid economic development and urbanization in China in the last few decades, PM2.5 pollution has become a serious public health concern. In the present study, the spatial variation patterns of PM2.5 and their trace metal concentrations during a haze episode were investigated in Beijing, Xi'an, Guangzhou, Xiamen, and Hong Kong. The volume concentrations of trace metals and Pb isotopic compositions revealed distinct patterns of PM2.5 pollution among these cities. Extremely high PM2.5 pollution with high volume concentrations of trace metals (especially As, Cd, Co, Pb, and Zn) was found in northern China. With such high PM2.5 pollution, the PM2.5 loading in haze days would account for approximately half or more than half of the contribution to whole-year PM2.5 loading in northern China. In contrast, lower PM2.5 loading and lower volume concentrations of most elements were observed in southern China. One exception is that higher volume concentrations of Cu, Ni, and V were observed, especially on Friday in southern China, suggesting that these metal pollutants might come from local vehicle and/or ship emissions. Different from the elemental volume concentration, the elemental mass concentrations do not exhibit noticeable spatial variations between northern and southern China, indicating that the overall trace metal concentrations of PM2.5 pollutants are comparable between northern and southern China. The Pb isotopic compositions in PM2.5 from northern China had lower 206Pb/207Pb ratios than those from southern China, suggesting a significant input of Pb from coal combustion in the northern region. Dusts from northwest deserts might also be a significant source of PM2.5 and trace metals in northern China, as indicated by back trajectory analysis of air mass transport. The carcinogenic and noncarcinogenic effects of PM2.5-associated trace metals via inhalation were assessed. The results suggest that a revision of the current safety levels of carcinogenic risk and hazard quotient might be necessary for future health risk assessment.

Differential distribution of PM<sub>2.5</sub>-associated trace metals in northern and southern megacities of China during a pollution episode

248th National Meeting (2014)

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Differential distribution of PM2.5-associated trace metals in northern and southern megacities of China during a pollution episode

Differential distribution of PM_2.5-associated trace metals in northern and southern megacities of China during a pollution episode