Urban and suburban variations in emission sources and quality-adjusted life year loss of PM2.5-bound PAHs in Beijing, China

Urban and suburban variations in PM2.5-bound PAH compositions, sources and their potential health risk in terms of quality-adjusted life year (QALY) loss were explored, taking Haidian and Fangshan as urban and suburban representatives in Beijing. The annual mean total concentration of 16 priority PAHs in Fangshan (26.95 ng/m3) was higher than that in Haidian (12.59 ng/m(3)). The concentration of PAHs was much higher during the heating season, with four-ring PAHs as the dominant species. The PMF-PSCF-CPF integrated source apportionment method identified the same three sources in both areas; however, the mass contribution of traffic emissions in Haidian (64.2%) was larger than that in Fangshan (54.7%), while the source of coal and natural gas combustion and the source of biomass combustion, petroleum volatilization and coke oven contributed less (26.4% and 9.3%) than those in Fangshan (32.1% and 13.2%). Potential risk contribution of vehicle emissions (Haidian: 2943.39 QALYs, 91.36%; Fangshan: 6360.58 QALYs, 83.25%) was much greater than its mass contribution because its emission contained more PAH species with high toxicity, such as BaP. QALY loss covers the content of mental health, integrates noncarcinogenic and carcinogenic effects, and can more comprehensively reflect the health loss of affected people, thus being a suitable indicator for determining priority control sources.