Sources-specific carcinogenicity and mutagenicity of PM2.5-bound PAHs in Beijing, China: Variations of contributions under diverse anthropogenic activities

To study source-specific carcinogenicity and mutagenicity of polycyclic aromatic hydrocarbons (PAHs) under diverse anthropogenic activities, PM2.5-bound PAHs were detected in Beijing in four periods. PAHs in Asia-Pacific Economic Cooperation meeting (APEC) was much lower than that in after-APEC period. The highest PAHs concentration was in heating period (303 ng/m(3)). Sources were quantified by Positive Matrix Factorization (PMF). In heating period, due to high emissions, weak diffusion, low degradation and evaporation, high contributions of all sources were observed, and both absolute and relative contributions of coal combustion increased. Changed contributions in during-APEC and after-APEC periods implied effectiveness of reinforced emission control, especially for coal combustion and vehicles. Furthermore, variations of sources-specific carcinogenicity and mutagenicity were investigated. In non-heating period, contributions of gasoline exhaust (38.4% TEQ: Toxic Equivalent Quantity, 33.7% MEQ: Mutagenic Equivalent Quantity) and diesel exhaust (53.8% TEQ, 57.9% MEQ) dominated both carcinogenic and mutagenic risks. Coal combustion sharply increased in heating period, attributing 27.5% TEQ and 21.7% MEQ. In during-APEC period, all contributions to carcinogenicity and mutagenicity were lower than those in after-APEC period, but "others" linked with regional transport contributed increased fractions (above 20%). Sources-specific carcinogenicity and mutagenicity under diverse anthropogenic activities, especially for APEC meeting with reinforced control, gave a new insight into assessment of control measures based on health risks.