Investigation into atmospheric PM2.5-borne PAHs in Eastern cities of China: concentration, source diagnosis and health risk assessment

This study investigated PM2.5-PAHs associations collected in Beijing, Jinan, and Shanghai in Eastern China. The results indicated that PM2.5 concentrations in Beijing, Jinan, and Shanghai were 125.7 mu g m(-3) (18.6-355.5 mu g m(-3)), 115.9 mu g m(-3) (44.2-345.4 mu g m(-3)), and 85.1 mu g m(-3) (24.3-232.8 mu g m(-3)), respectively. The PAH concentrations in terms of PM2.5 in Beijing, Jinan, and Shanghai ranged from 23.2 to 819.8 ng m(-3), 25.7 to 727.1 ng m(-3), and 8.5 to 133.9 ng m(-3), respectively. PAH concentrations were found to be positively correlated with PM2.5 concentration in Beijing and Shanghai. The compositions of PAHs in PM2.5 in Beijing and Jinan were almost the same: 11% low ring, 80-82% middle ring, and 7-9% high ring. However, Shanghai had a different composition. Source apportionment indicated that the incomplete combustion of coal and diesel and gasoline emissions were the main sources of PAHs in PM2.5 in all three cities, whereas Shanghai had a greater contribution from liquid fossil fuels. The values for the health risk assessment estimated by the benzo[a] pyrene equivalent concentration in Beijing and Jinan were 2.39 x 10(-6) and 2.57 x 10(-6), respectively, thus both exceeding the 1 x 10(-6) limit (USEPA) considered likely to pose an inhalation cancer risk to people. Shanghai, however, had a risk estimate of 5.05 x 10(-7), which is still in a safe range. This study is the first to simultaneously monitor the PAHs in PM2.5 in three cities in Eastern China and may point to a long-range transportation of PM2.5-PAHs from Beijing to Jinan and partially to Shanghai.