Pollution characteristics, source analysis, and health risk assessment of polycyclic aromatic hydrocarbons in atmospheric PM2.5: a case study in Xi'an, China.

Air samples were collected at the Lianhu (urban) and Yanta (semi-urban) regions between January 2020 and December 2023 to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) in Xi'an, which is an important tourist city in China. The concentration of PAHs was ascertained using liquid chromatography. The concentration of ΣPAHs in Xi'an was 0.13-105.02 ng/m, while the concentration of ΣPAHs for the sampling regions at Lianhu and Yanta were 0.13-105.02 ng/m and 0.34-82.64 ng/m, respectively. PAHs with 4-5 rings were the predominant PAHs pollutants in Xi'an, mainly from coal combustion and automobile exhaust. Risks through inhalation to three groups, adult males, adult females, and children, were estimated. The incremental lifetime cancer risk (ILCR) value for local adults and children were less than 10, considered to be at a safe level. However, the ILCR is relatively close to the minimum risk threshold (10), and it still needs to be highly valued.