北京市冬季大气PM_(10)中二噁英的污染水平与分布特征

Pollution levels and spatial distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the atmospheric PM_(10) of Beijing in winter

在北京市市区/交通干道(A地质大学东门、B地质大学测试楼顶),工业区(C首钢焦化、D高井热电厂)和背景点(E十三陵),同时采集了冬季大气颗粒物PM_(10)样品.利用US EPA 1613B方法,采用同位素稀释、高分辩率气相色谱/高分辩率质谱(HRGC/MS)联用技术,对比分析了PM_(10)中17种二噁英(PCDD/Fs)的浓度水平和区域分布特征.结果表明,5个采样点PM_(10)的质量浓度范围是140—264μg·m^(-3),日均值为184μg·m^(-3)比国家二级标准(150μg·m^(-3))高23%.所有采样点17种PCDD/Fs的总浓度范围1.96—4.80 pg·m^(-3),平均值3.69 pg·m^(-3),总毒性当量∑TEQ范围是148—353 fg I-TEQ·m^(-3),平均271 fg I-TEQ·m^(-3);PCDD/Fs污染水平最高出现在工业区,其次是市区,背景点最低.

PM10 samples were collected concurrently at five sites:two urban sites(the east gate of China University of Geosciences(CUGB)and the roof of a testing building within CUGB),two industrial sites(coking plant of Capital Steel Plant and a thermoelectric plant)and a background site(Ming Tombs)in Beijing China in winter.The concentration and spatial distribution of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)congeners were analyzed with isotope dilution and high resolution gas chromatography/high resolution mass spectrometry(HRGC/HRMS)based on US EPA 1613 B method.PM10 concentrations were in the range of 140—264μg·m-3 with a mean value of 184μg·m-3,which was 23%higher than the second class daily average standard(150μg·m-3).∑17PCDD/Fs concentrations varied from 1.96—4.80 pg·m-3,with an average concentration of 3.69 pg·m-3.The toxic equivalents(TEQs)varied from 148—353 fg I-TEQ·m-3 with an average value of 271 fg I-TEQ·m-3.The highest PCDD/Fs pollution level was observed at the industrial sites,followed by urban sites and background site in Beijing.