摘要
目的 分析北京市丰台区大气细颗粒物(fine particulate matter,PM2.5)中多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的污染特征,并对其污染来源进行初步识别.方法 2015-2020年每月定期采集北京市丰台区某社区的大气PM2.5样品,采用高效液相色谱法测定PM2.5样品中16种PAHs的含量,分析比较不同季节、不同监测时段下的PAHs的污染特征;采用特征比值法对大气PM2.5中PAHs的污染来源进行初步识别.结果 北京市丰台区某社区大气PM2.5及PM2.5中16种PAHs(∑PAHs)质量浓度中位数分别为86 µg/m3和10.70 ng/m3;大气PM2.5中PAHs的污染水平呈现明显的季节变化趋势,即冬季＞(秋季和春季)＞夏季;采暖期大气PM2.5中PAHs显著高于非采暖期;单体PAHs中荧蒽占比最高,其次为苯并[b]荧蒽、苯并[g,h,i]苝、䓛和苯并[a]芘;4环PAHs占比为最高(36.81％),采暖期4环以上高环数PAHs占比高于非采暖期.5种特征比值(3 环+4 环)/(5 环+6 环)、BaP/BghiP、Flu/(Flu+Pyr)、IP/(IP+BghiP)和 BaA/(BaA+Chr)的均值分别为 2.11、2.17、0.61、0.43和0.39,提示PAHs污染主要来自本地污染,煤/生物质燃烧源和交通污染为其主要污染来源.结论 2015-2020年北京市丰台区大气PM2.5中PAHs的污染水平具有明显的季节变化特征,采暖期大气PM2.5中PAHs浓度水平显著高于非采暖期.煤/生物质燃烧和交通污染是丰台区大气PM2.5中PAHs的主要污染来源.
Abstract
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.
万方数据