Seasonal variation, sources and health risk assessment of polycyclicaromatic hydrocarbons in different particle fractions of PM2.5in Beijing,China

Özet

The ratio of SO2/NO2together with PM2.5/CO was applied to explain the source of particulate matters (PM)pollution in Beijing. Polycyclic aromatic hydrocarbons (PAHs) bounded with ultrafine particles were in-vestigated as well. A total of 188 graded PM in four-stage size segregated aerosol particles were collected andanalyzed by GC-MS in 2016 to investigate the sources and distribution patterns of PAHs in metropolis-Beijing. Asignificant seasonal variation of 16 PAHs in PM2.5around in Beijing was observed with 32.93 ± 15.19 ng m−3,17.77 ± 8.08 ng m−3, 31.61 ± 12.67 ng m−3and 78.06 ± 40.97 ng m−3in spring, summer, autumn andwinter, respectively. The ratio of SO2/NO2demonstrated that vehicle emissions significantly contributed to airpollution. On the contrary, the lower ratio of PM2.5/CO showed high direct discharge from combustion. Seasonaldistribution patterns of PM0.2/PM2.5suggested that abundant secondary aerosols were produced in the autumnand winter. The spread of pollutants was not significant in winter. Both the combustion of fuel and coal were theprimary sources of PM2.5-bound PAHs. A health risk assessment was represented by benzo[a]pyrene equivalent(BaPeq) indicating potential cancer risk in Beijing. Furthermore, the lifetime excess cancer risk (ECR) was3.00 × 10−4, which was higher than the guidelines of USEPA and European Commission, indicating high car-cinogenic risk of PM2.5in Beijing. Therefore, more strictly control measures should be taken to reduce PAHsemissions from coal and vehicle.