Potential threat of heavy metals and PAHs in PM2.5 in different urban functional areas of Beijing

Beijing, as the capital of China, is one of the most populous cities in the world. With the fine particulate matter pollution being increasingly serious, daily exposure to hazardous ingredients caused more and more attention. Current research concerning risk evaluation in Beijing was relative less. In November, 2013, samples were collected in seven different functional areas of Beijing, so as to better understand the risk to human health caused by particle matter pollution in this region. PM2.5 pollution in rural and urban Beijing was relative high under haze–fog days in comparison with non haze–fog value. Zn and Ba showed the highest concentration levels among non-carcinogenic metals. The non-carcinogenic metal concentration at all the sites ranged in the same order: Ce, Pb, Cu, V and Sb. Higher ring PAHs (with four to six rings) were the dominant species and constituted more than 90% of the Σ14PAHs. Pb (4.34×10−4 for men, 3.73×10−4 for women) presented the maximum risk level for non-carcinogenic heavy metals in the whole study area. While, risk levels of Cr at residential areas, schools, Olympic Park and rural countryside exceeded the limit for adults. In haze–fog days, the carcinogenic PAH risk level in each functional area ranged in the order: rural countryside>inner suburban district>Olympic Park>city central>schools>ecological reserve>residential areas. To some extent, benzo(a)pyrene may had a potential risk to adults, and other carcinogenic PAHs were all under average risk acceptance. •Daily PM2.5 concentration and chemical composition in Beijing were studied.•Urban fine particle pollution was much worse than that in rural areas.•Health risk of both heavy metal and PAHs was evaluated in different functional areas of Beijing.•Cr and BaP may have potential risk to environment to some extent in some areas.