Seasonal and spatial variations of PM-bounded PAHs in a coal mining city, China: Distributions, sources, and health risks.

Atmospheric polycyclic aromatic hydrocarbons (PAHs) emitted from coal combustion has become the major contributor of atmospheric PAHs in China and caused worldwide concern due to their adverse effects on human health and ecosystem. In this work, the abundance, distribution, source and health risk assessment of ambient PM-bounded PAHs were studied in all seasons from a typical coal resource city in China. The spatial distribution characteristics of PM-bounded PAHs were also investigated, which cover 6 functional zones including industrial area, mining area, commercial district, education area, residential area and control area, respectively. The average concentrations (in ng/m) of 16 EPA priority PAHs in PM in spring, summer, autumn and winter were 194 ± 11.1, 161 ± 14.0, 183 ± 14.1 and 213 ± 19.2, respectively, and with an annual average of 188 ± 21.8. The composition distribution of PM-bounded PAHs in each functional zone showed that 4-rings PAHs were dominated in all seasons, followed by 3-rings and 5-rings. Principal component analysis (PCA) and diagnostic ratio indicated that the main PAH sources were coal combustion, traffic and biomass combustion. Health risk assessment analysis (BEQ) suggested that the residential exposure to PAHs in the mining and commercial areas, particularly in winter season, may pose a greater cancer risk than people living in other parts of Huainan city. The maximum BEQ values were found at mining and commercial areas, which were mainly influenced by the emissions from gasoline or diesel vehicles, coal and biomass combustion. Both inhalation and skin contact have great influence on the cancer risk of residents in Huainan city.