Pollution characteristics, sources and toxicity evaluation of PAHs in atmospheric PM2.5 in Shenyang

This study was to assess the pollution levels, compositional characteristics, sources, and toxicity changes of polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 in Shenyang. 98 samples were analyzed for PAHs at seven locations in Shenyang on December 15–21, 2020, and April 8–16, 2021. The detection rate of PAHs was 100% for 98 samples, in which Fla, Pyr, Phe, Chr and Flu with medium and low rings were predominant. During the heating period, the total concentration of PAHs ranged from 59.05 to 131.15 ng/m 3 , and the average concentration was 95.03 ng/m 3 . The concentration of PAHs in the non-heating period was 13.38 ~ 47.52 ng/m 3 , and the average value was 35.51 ng/m 3 . The highest concentration of PAHs was found in residential areas in southern Shenyang. The positive matrix factorization (PMF) model showed that the sources of PAHs in Shenyang were motor vehicle exhaust emissions, coal and biomass combustion, and oil pollution emissions. During the heating period, coal and biomass combustion contributed 44.2%, while motor vehicle exhaust emissions accounted for 44.8% in the non-heating period. According to the evaluation of the toxic equivalent concentrations of PAHs, the toxic concentrations in all areas of Shenyang except rural areas were all higher than the standard concentrations prescribed by China and WTO. The toxic equivalent concentrations in residential areas were highest. These results presented the PAHs concentration in Shenyang and provided implications for air pollution control measurements.