Long-term spatiotemporal variation and lung cancer risk of atmospheric polycyclic aromatic hydrocarbons (PAHs) in the Yangtze River Delta, China.

The Yangtze River Delta (YRD), which is the most developed region in China, suffers from atmospheric polycyclic aromatic hydrocarbons (PAH) pollution. However, the long-term spatiotemporal variation of atmospheric PAHs and the lung cancer risk caused by PAH exposure in the YRD remain unclear. Herein, we simulated the daily atmospheric concentration of benzo[a]pyrene (BaP, the most carcinogenic PAH) from 2001 to 2016 using an atmospheric transport model. During this period, the atmospheric BaP concentration showed a general trend of first increasing and then decreasing (average BaP concentration = 0.50 ± 0.12 ng/m 3 ) and was highest in 2005 (0.72 ng/m 3 ). Moreover, the BaP concentration in Jiangsu and Shanghai was 5.17- and 4.98-fold higher than that in Zhejiang. BaP pollution was severe in Jiangsu during the winter. The average area proportion of BaP exceeding the national standard in winter in Jiangsu was 69.09%. The population-weighted incremental lifetime cancer risk from 2001 to 2016 ranged 6.67 × 10 -6 -1.50 × 10 -5 , and the excess lung cancer cases ranged 1054-2130. Compared with 2005, excess lung cancer cases in the YRD decreased by 49.49% in 2016. Reducing BaP pollution in winter in Jiangsu is crucial for reducing lung cancer risk in the YRD.