Source apportionment and toxicity assessment of PM2.5-bound PAHs in a typical iron-steel industry city in northeast China by PMF-ILCR

Abstract

This study was designed to evaluate the occurrence and variation in concentrations, sources and cancer risk of PM2.5-bound PAHs. Airborne PM2.5-bound PAHs were sampled during a one-year campaign (2014–2015) in Anshan city, a typical iron and steel city in northeast China. A total of 374 PM2.5 samples were collected. A source-oriented positive matrix factorization (PMF) model and PAH diagnostic ratios were used to investigate the potential sources of PAHs in the atmospheric environment of Anshan, and the lifetime cancer risk of the population associated with PAHs through inhalation exposure was assessed by a PMF-ILCR model. Concentrations of PM2.5 and 16 PAHs ranged from 13.55 μg/m3 to 315.96 μg/m3 and 5.08 ng/m3 to 520.02 ng/m3, respectively. These values were higher in winter. PAH content from stationary sources and biomass combustion was higher than from other sources. Through the coefficient of divergence and localized PAH diagnostic ratio methods, we concluded that PM2.5-bound PAHs in Anshan originated mainly from the following sources: biomass combustion, vehicle emissions, fugitive dust, coking dust and natural gas emissions. Based on the source-oriented PMF model, coal combustion, fugitive dust, vehicle emissions, coking dust, and biomass combustion were the main sources contributing to PM2.5, accounting for 26.3%, 24.6%, 21.9%, 18.0%, and 6.3% of PM2.5, respectively. According to the PMF-ILCR model results, ILCR risks estimated for adults and children were respectively 1.19 × 10−5 and 8.55 × 10−6 in winter, higher than in other seasons, and higher than the threshold value (10−6). Together, vehicle emissions (diesel exhaust and gasoline exhaust), coal combustion and coking dust, contributed to over 86% of the cancer risk associated with PM2.5-bound PAHs exposure in Anshan.