Seasonal variation and health risk assessment of atmospheric PM 2.5 -bound polycyclic aromatic hydrocarbons in a classic agglomeration industrial city, central China

Sixty atmospheric sample concentrations of PM 2.5 and polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 were analyzed in distinct seasonal variations from a classic agglomeration industrial city. The concentrations of PM 2.5 ranged from 6.96 to 260.06 μg/m 3 with an average of 177.05 μg/m 3 . Only 38% of the sampling days were superior to the 24-h limit value (75 μg/m 3 ) of ambient air quality standards (AAQs), and the samples from autumn and winter exceeded the limit value. The total PAHs ranged from 1.51 to 44.51 ng/m 3 with an average of 10.65 ng/m 3 . The highest and lowest concentrations of total PAHs appeared in winter and summer with averages of 22.56 and 4.03 ng/m 3 , respectively. Correlation analysis revealed that high-molecular-weight PAHs (HMW-PAHs) (4-, 5-, 6-ring PAHs) were significantly and negatively correlated with temperature and water-soluble total organic carbon (WTOC), and significantly correlated with water-soluble total nitrogen (WTN). The 4-, 5- and 6-ring PAHs were dominant, especially those of 4-ring PAHs, which were above 30% of the total PAHs in each season. Source apportionment indicated that PM 2.5 -bound PAHs in Huangshi were mainly derived from pyrogenic source, vehicle exhaust, coal combustion, and biomass burning. Incremental lifetime cancer risks (ILCRs) showed no potential carcinogenic risk from the PM 2.5 -bound BaP-eq. ILCRs in winter were the highest, and the risks for adults were approximately an order of magnitude higher than those for children.