环境地球化学国家重点实验室知识库

The polycyclic aromatic hydrocarbons (PAHs) bound to fne particulate matter (PM2.5) can cause long-term adverse health consequences and are a public concern. A total of 144 PM2.5-bound PAHs samples collected from Guiyang City, a typical plateau montane area in southwest China, from September 2012 to August 2013 were investigated to clarify their concentration, distribution, and potential sources. The health exposure risk also was evaluated. The samplers equipped with 90-mm glass fbre flters were operated at a fow rate of 100 L min−1 for 24 h. The concentrations of the 16 PAHs (US EPA priority) were analysed by using ultra performance liquid chromatography equipped with photo diode array detector. Diagnostic ratios and back-trajectories were performed for the 16 PAHs sources apportionment. The results showed that the 16 PAHs ranged from 2.9 to 231 ng m−3 with an annual average of 41±21 ng m−3. The PAHs concentrations exhibited obvious seasonal variation, with higher levels in winter than in summer. Diagnostic ratios indicated that PAHs mainly originated from the combustion of coal and biomass, followed by the emission of vehicle exhaust. Cluster analyses on back-trajectories illustrated that approximately 34% of the air mass came from abroad, as far as Laos and Vietnam, in summer, whereas more than 90% of the air mass came from domestic sources in winter. The lifetime excess cancer risk from exposure to PAHs was 3.63×10−4, approximately 360 times higher than the health guideline (10−6) recommended by the US EPA, refecting a high risk of cancer.