Atmospheric PM2.5 samples were collected at three representative sites (Industry, Downtown Traffic and Botanical Garden) in Wuhan during autumn and winter of 2011—2012. The composition of 27 polycyclic aromatic hydrocarbons (PAHs) in PM2.5 samples were measured by ultrasonic agitation followed by GC/MS method. The diagnostic ratios and Principal component analysis/Multiple linear regression analysis (PCA/MR) were used to determine the major source contributions to PAHs in PM2.5. The results showed that the total mass concentrations of PAHs at three sites ranged from 24.705 to 112.490 ng·m-3, which varied temporally and spatially with higher concentration in winter than in autumn, Industry site > Downtown Traffic site > Botanical Garden site. The abundance order for PAHs with various rings was the following:5-ring>4-ring>2-3-ring>6-7-ring. The high percentage of 4-and 5-ring suggested the main pollution sources come from coal combustion and vihical exhaustion. The evaluation of diagnostic ratios showed that coal combustion and vehicle exhaust are major pollution sources, which is similar to the results from Principal component analysis. Coal combustion was found the biggest contributor (55%) to PAHs at Industry site, while the other sources come from gasoline and diesel combustion, coke smoke and light oil combustion. In contrast, vehicle exhaust (34%) and nature gas combustion (25%) were the main sources at the Downtown Traffic site. The wood combustion accounts for 46% of PAHs at Botanical Garden site.% 采集了2011—2012年武汉市工业区、交通区和植物园的3个功能区的秋冬2季大气PM2.5样品，采用超声提取预处理和GC/MS分析检测了PM2.5中27种PAHs，探讨了其时空分布特征，然后运用主成分分析/多元线性回归法解析了PAHs的来源。结果表明：PAHs的质量浓度范围为24.705~112.490 ng·m-3，PAHs的质量浓度分布呈现出工业区>交通区>植物园的规律；冬季PAHs质量浓度高于秋季等特征。不同环数PAHs质量浓度呈现出规律变化为：5环>4环>2-3环>6-7环，4环、5环的 PAH 含量比例高表明机动车尾气和煤燃烧排放是主要排放源。不同功能区化合物的比值指示来源略有不同，但总体指明了武汉主要污染源来自燃煤和机动车尾气的排放。源解析结果显示，工业区的污染源主要来自于燃煤，其贡献率为55%，其次为汽油燃烧、柴油燃烧、焦炉和轻质油燃烧。在交通区中，车辆尾气排放(34%)和天然气燃烧(25%)的贡献较大，其次是烹饪、燃煤及木材燃烧。植物园对照区的主要污染源分别是木材燃烧、燃煤、天然气燃烧、车辆排放和烹饪，其中木材燃烧(46%)的贡献最大。
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