| PAHs pollution has been proved to be mutagenic and/or carcinogenic, and thus directly posing threats to human population. So the study of PAH pollution is important. But for the limited conditions, the objectives of this paper are confined only to the study of PAHs levels, their distribution patterns, and the seasonal variation characterization and source identification of PAHs bound to TSP in Changsha.Sampling of ambient air TSP-bound PAHs was performed at several sites (A, B, C) during summer and autumn of 2008 in Changsha, Hunan province, P.R. China. Samples were collected from three sites:the city environmental protection agency of Changsha (A), the Middle School Attached to Hunan Normal University (B) and Yuhua district (C).Glass fiber filters were used to determine the concentration of total suspends particulate (TSP). Particulate matter was extracted in an ultrasonic bath. The concentrated extracts were fractionated by column chromatography to separate PAHs from other polar organic interfering materials. The PAHs were identified by means of a gas chromatography coupled with a mass spectrometry detector. The detection mode used for the identification was selective ion monitoring (SIM).According to the sampling results, TSP concentrations ranged from 195.5 to 351.7μg/m3 in the summer and from 165.6 to 250.6μg/m3 in the autumn. There was no significant correlation between temperature and the level of TSP.The total of 16 PAHs concentrations of summer at site A, B, C ranged from 30.009 ng/m3 to 35.814 ng/m3,18.066 ng/m3 to 22.446 ng/m3, and 22.640 ng/m3 to 30.030 ng/m3, respectively; while the values for autumn at site A, B, C were 8.314 ng/m3 to 31.703ng/m3,15.191ng/m3 to 19.204ng/m3, and 12.448ng/m3 to 18.626ng/m3, respectively. The mean concentrations of PAHs at A site were 0.57 times higher than those measured at B site, and 0.38 times higher than at C site.The ratios of individual PAHs ranged from 0.058 to 11.711 for site A, from 0.192 to 3.635 for site B and from 0.060 to 10.692 for site C. These indicate no significant seasonal variations of individual PAHs concentrations. This fact suggested that the ambient PAHs could be affected by vehicles and stationary sources which were a few seasonal differences.Different profiles and distribution patterns of individual PAHs were characteristic of different pollution sources. These results suggested that the major polluting sources in the Changsha region during the studied period were the burning of fuels, such as diesel oil and gasoline, wood and coal.As the PC A conclusion, in summer, the major sources of PAHs were vehicle emissions, natural gas combustion, and combustion. In autumn, the major sources of PAHs were gasoline emissions, combustion source, and natural gas combustion, and coke oven.The determined factors accounted for over 85.8% and 89.9% of the total data variance for summer and autumn samples, respectively. Varimax rotated factor analysis for samples taken during summer and autumn samples showed three and four possible factors indicating three and four different contributing sources for the PAHs during the two seasons, respectively.
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