北京市大气颗粒物中正构烷烃污染特征的研究

Pollution Characteristics of N-alkane in Aerosol Particles of Beijing

利用中流量采样器于2011年3-12月对北京西三环地区大气颗粒物进行分级采样,并利用GC-MS对颗粒物中正构烷烃含量进行测定。对不同粒径颗粒中C10-C2415种正构烷烃的测定分析表明,PM2.5、PM5和PM10中正构烷烃的年均质量浓度分别为94.24 ng/m3、114.20ng/m3和124.96 ng/m3;正构烷烃总质量浓度的季节变化趋势为：冬季〉春季〉秋季〉夏季,且主要分布在在细粒子中（PM2.）5;正构烷烃在不同粒径粒子中质量浓度比（ρ2.5/ρ1）0正构烷烃、（ρ2.5-5/ρ1）0正构烷烃、（ρ5-10/ρ1）0正构烷烃分别为：春季为78.2%、13.2%、8.5%,夏季为68.6%、19.8%、11.6%,秋季为74.4%、13.8%、11.8%,冬季为76.4%、17.6%、6.1%。主碳峰为24和23,碳优势指数（CPI）2为0.56~0.57,表明正构烷烃主要来源于汽车尾气和化石燃料的燃烧等人为活动。

This paper reported on an investigation aiming at the air pollution characteristics in Beijing regarding in aerosol particles,involving the aerosol particles sampling conducted over the city’s urban areas during the period of March to December,2011.GC-MS was used to detect homolog of n-alkane including C10 to C24,and the mean annual combined concentrations of Σ15 n-alkane in PM2.5 and PM10 were measured.In general,concentrations of Σ15 n-alkane,which was preferentially accumulated in smaller particulates e.g.PM2.5,varied seasonally,i.e.,highest in winter,followed by spring,autumn and summer.It was concluded that n-alkane in particles had been mainly originated from human activities such as fossil fuel combustion and vehicle exhaust,