Pollution characteristics and sources of PM 2.5-bound polycyclic aromatic hydrocarbons in Fengtai district,Beijing,China
Objective To analyze the pollution characteristics and primarily identify the sources of fine particulate matter(PM2.5)-bound polycyclic aromatic hydrocarbons(PAHs)in Fengtai District,Beijing,China.Methods Sixteen PM2.5-bound PAHs were measured using high-performance liquid chromatography in atmospheric PM2.5 samples collected monthly in a community of Feng-tai District from January 2015 to December 2020.The pollution characteristics of PM2.5-bound PAHs were analysed for different sea-sons and monitoring periods.Characteristic ratios were used for preliminary identification of the pollution sources of PM2.5-bound PAHs.Results The median values of atmospheric PM2.5 and 16 PM2.5-bound PAHs(∑PAHs)were 86 μg/m3 and 10.70 ng/m3,re-spectively.Seasonal variations of the concentrations of PM2.5-bound PAHs followed the order of winter＞(autumn and spring)＞summer.The concentrations of PM2.5-bound PAHs were significantly higher during the heating period than during the non-heating period.Flu-oranthene accounted for the highest proportion in PM2.5-bound PAHs,followed by benzo[b]fluoranthene,Benzo[g,h,i]perylene,chrysene,and benzo[a]pyrene.PAHs with four rings had the highest proportion(36.81％).The concentrations of PAHs with four or more rings were higher in the heating period than in the non-heating period.The mean values of five characteristic ratios,i.e.,(three-rings+four-rings)/(five-rings+six-rings),BaP/BghiP,Flu/(Flu+Pyr),IP/(IP+BghiP),and BaA/(BaA+Chr),were 2.11,2.17,0.61,0.43,and 0.39,respectively.These characteristic ratios indicated that the pollution of PAHs primarily originated from local sources,and that coal/biomass combustion and traffic emission were the main sources of PM2.5-bound PAHs in Fengtai District.Conclusion PM2.5-bound PAHs showed obvious seasonal variations in Fengtai District from 2015 to 2020;the concentrations of PM2.5-bound PAHs were significantly higher in the heating period than in the non-heating period.Coal/biomass combustion and traffic emission were the main sources of PM2.5-bound PAHs in Fengtai District.
fine particulate matter(PM2.5)polycyclic aromatic hydrocarbonpollution characteristicsource
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