Characteristics and Health Risks of Polycyclic Aromatic Hydrocarbons and Nitro-PAHs in Xinxiang, China in 2015 and 2017

Fine particulate matter (PM(2.5)) samples were collected in the summer and winter of 2015 and 2017 in Xinxiang, China. Nine polycyclic aromatic hydrocarbons (PAHs) and three nitro-PAHs (NPAHs) in PM(2.5) were detected via high-performance liquid chromatography (HPLC). The PAHs concentration in summer and winter decreased from 6.37 ± 1.30 ng/m(3) and 96.9 ± 69.9 ng/m(3) to 4.89 ± 2.67 ng/m(3) and 49.8 ± 43.4 ng/m(3) from 2015 to 2017. NPAHs decreased in winter (from 1707 ± 708 pg/m(3) to 1192 ± 1113 pg/m(3)), but increased in summer from 2015 (336 ± 77.2 pg/m(3)) to 2017 (456 ± 312 pg/m(3)). Diagnostic ratios of PAHs indicated that petroleum combustion was the main emission source in summer, and pollutants originating from the combustion of petroleum, coal and biomass dominated in winter. The 2-nitrofluoranthene (2-NFR)/2-nitropyrene (2-NP) ratio in this study demonstrated that the OH radical pathway was the main pathway for the formation of 2-NP and 2-NFR. The mean total benzo[a]pyrene-equivalent concentrations (BaP(eq)) and incremental lifetime cancer risk (ILCR) values decreased from 2013 to 2017. The high value of total BaPeq in the winter of 2017 in Xinxiang revealed that a high-risk of cancer remained for residents. The results of this study demonstrate that the decreases in PAHs and NPAHS concentrations from 2015 to 2017. Combined with reducing gaseous pollutants concentration, the reduction in this study might be attributable to emissions reductions by implementing the air pollution control regulations in Xinxiang city in 2016.