In this study, 30 PM2.5 samples were collected from the atmosphere in Changchun City in the autumn of 2017. The concentration and composition characteristics of 17 polycyclic aromatic hydrocarbons (PAHs) in the samples were analyzed by gas chromatography mass spectrometry (GC-MS). The diagnostic ratio and principal component analysis method were used to determine the source of PAHs pollution. The health risk assessment was carried out by both calculating the equivalent carcinogenic concentration of benzo(a)pyrene and the lifetime risk of cancer. Results show that the average PM2.5 concentration in autumn in Changchun is (50.84±12.23) μg·m-3, and the content of organic carbon (OC) and elemental carbon (EC) are (17.07±5.64) μg·m-3 and (1.33±0.75) μg·m-3, respectively, accounting for 37% of the total PM2.5. The total concentration of PAHs is (15.69±5.93) ng·m-3, which was dominated by medium- to high-ring-number PAHs, accounting for 84.26% of total PAHs. The atmospheric PAHs in Changchun mainly originate from motor vehicle exhaust emissions (44.48%) > coal combustion (29.16%) > biomass burning (26.36%), local transportation (gasoline vehicles) emissions being the main source of pollution. The average carcinogenic concentration of benzo(a)pyrene is in the range of 1.55 ng·m-3 and 5.38 ng·m-3, and the average carcinogenic equivalent concentration is (6.44±1.53) ng·m-3, which is generally considered a slight pollution level. The ingestion of PAHs by breathing is the most harmful to the health of adult women, followed by adult males and children, however since the lifetime carcinogenic risk value of the entire population did not exceed 1×10-6, their health risks are considered to be at acceptable levels.
Keywords: Changchun; PM2.5; health risks; polycyclic aromatic hydrocarbons; source analysis.