FURTHER INSIGHTS INTO THE COMPOSITION, SOURCE, AND TOXICITY OF PAHS IN SIZE-RESOLVED PARTICULATE MATTER IN A MEGACITY IN CHINA

Concentrations of particulate matter with an aerodynamic diameter less than 10 m (PM10) and PM with an aerodynamic diameter less than 2.5 m (PM2.5), and 16 polycyclic aromatic hydrocarbons (PAHs) were measured. The average concentrations of PM10 and PM2.5 reached 209.75g/m(3) and 141.87g/m(3), respectively, and those of sigma PAHs were 41.46ng/m(3) for PM10 and 36.77ng/m(3) for PM2.5. The mass ratio concentrations were 219.23g/g and 311.01g/g in PM10 and PM2.5, respectively. Three sources and their contributions for PAHs were obtained. For individual input mode, diesel exhaust contributed 46.77% (PM10) and 41.12% (PM2.5) for mass concentration and 48.69% (PM10) and 39.47% (PM2.5) for mass ratio concentration; gasoline exhaust contributed 31.02% (PM10) and 39.47% (PM2.5) for mass concentration and 28.95% (PM10) and 36.46% (PM2.5) for mass ratio concentration; and coal combustion contributed 22.22% (PM10) and 19.41% (PM2.5) for mass concentration and 22.36% (PM10) and 15.89% (PM2.5) for mass ratio concentration. For combined input mode, the same source categories were obtained. Source contributions to PM10 and PM2.5 were diesel exhaust (40.70% and 36.64%, respectively, for mass concentration; 49.19% and 38.47%, respectively, for mass ratio concentration), gasoline exhaust (35.09% and 38.47%, respectively, for mass concentration; 32.50% and 33.43%, respectively, for mass ratio concentration), and coal combustion (24.21% and 24.89%, respectively, for mass concentration; 18.31% and18.17%, respectively, for mass ratio concentration). Source risk assessment showed that vehicle emission was a significant contributor. The findings can help elucidate sources of PAHs and provide evidence supporting further applications of the Unmix model and additional studies about PAHs. Environ Toxicol Chem 2015;34:480-487. (c) 2014 SETAC