[Source Analysis and Health Risk Assessment of PAHs in PM_2.5 During Winter in Liaocheng City]

To investigate the mass concentrations, sources, and health effects of polycyclic aromatic hydrocarbons (PAHs) in ambient particulate matter (PM) in Liaocheng City during winter, 14 types of PAHs in PM_2.5 were determined from January to February of 2017. The sources of the PAHs were analyzed by using diagnostics ratios and the principal component analysis (PCA)-multiple linear regression (MLR) model,and the health risk of PAHs was assessed by BaP equivalent concentrations (BaP_eq) and incremental lifetime cancer risk (ILCR). The results showed that the mass concentrations of PAHs in PM_2.5 during winter were (64.89±48.23) ng·m^-3, Fla, Pyr, and Chry were predominant species, accounting for 15.5%, 12.8%, and 12.7% of the total concentrations of PAHs, respectively. Moreover, the ring distribution of the PAHs was dominated by four-ring PAHs. The pollution during the pre-Spring Festival and firework Ⅱwere the most severe during the sampling period. The results of the PCA-MLR model suggested that PAHs originated mostly from coal burning, biomass burning, and vehicle emissions. The toxicity exposure index (TEQ) in Liaocheng City during winter was (6.37±4.92) ng·m^-3. The results of the risk model revealed that the ILCR of adults was higher than that of children, and both groups of ILCR for winter were in the range of the risk threshold. This suggests that a potential risk in terms of inhalation PAH exposure for residents in Liaocheng City.