中文摘要：

分析了武汉市2009年冬夏两个季节大气PM2．5的浓度，并用气相色谱／质谱（GC／MS）技术研究了烃类化合物组成及变化特征。结果表明，PM25的质量浓度为25．0-302．4μg／m^3，冬季明显高于夏季。检测出nC11～nC34正构烷烃，高碳数部分奇偶优势明显，碳优势指数（CPI）在1．1～2．9，具有高等植物蜡和人为源输入特征，冬夏季分布差异较大；藿烷和甾烷的普遍检出证实了大气颗粒物已明显受到化石燃料残余物的污染，且在冬季浓度相对较高；高环数多环芳烃含量较高，特征性诊断参数表明机动车排放相对较大。

英文摘要：

Series of atmospheric PM2.5 samples were collected from an urban site of Wuhan in summer and win-ter of 2009. These PM2.5 samples were analyzed by gas chromatography-mass spectrometry （GC-MS） method to in- estigate the composition and variation of hydrocarbons in PM2. 5. The result indicated that the concentration of PM2.5 was ranged 25.0-302.4/μg/m^3 ,with higher loading in winter than in summer. The n-alkanes with carbon number of 11 to 34 was detected in PM2. 5 samples, high carbon number alkanes possessed significant odd even predominance with carbon predominance index （CPI） was between 1.1 and 2.9,and great difference existed in the hydrocarbons distribu-tion between winter and summer. These characteristics indicating the mixed inputs of PM2.5 from higher plant wax and antbropogenic source. The detected hopanes and steranes were indicative of fossil fuels residue input, while the influ- ence was relatively predominant during winter period. The high molecule weight PAHs were significant components of hydrocarbons, together with diagnostic parameters,indicating the PM2.5 in Wuhan was predominantly polluted by mo-tor vehicle traffic activity.