Unveiling the pollution and risk of atmospheric (gaseous and particulate) polycyclic aromatic hydrocarbons (PAHs) in a heavily polluted Chinese city: A multi-site observation research

Linfen, one of the most polluted cities in China, releases huge amounts of polycyclic aromatic hydrocarbons (PAHs) into the atmosphere. The pollution characteristics of Linfen's PAHs, along with their emission sources and health risks, were scarcely discussed. This study conducted a multi-site observation campaign in Linfen during the non-heating and heating periods (2018–2019) using passive air samplers. Sixteen PAHs were analyzed for the gaseous and particulate samples collected at the 15 sites in the urban, rural, and background areas. The PAH concentrations in Linfen's atmosphere were 225.7 ± 81.9 ng m⁻³ during the heating period and 139.9 ± 47.5 ng m⁻³ during the non-heating period, annually averaged to 168.1 ± 58.6 ng m⁻³, which was predominantly contributed by the rural and urban emissions. Combustion was highly responsible for the PAHs, including the burning of coal for industrial production and winter heating, coupled with the utilization of oils by automobile engines. The spatiotemporal variations of PAHs were associated with the discrepancy of emission intensity rather than that of emission type. The BaP equivalent concentrations for the rural and urban areas were 1-2 orders of magnitude higher than the various international standards, indicating the considerable carcinogenic risk for the majority of local residents. These findings are informative for better understanding the atmospheric PAH pollution in a typical resource-based Chinese city.