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The purpose of this study is to understand the characteristics of pollution and distribution of polycyclic aromatic hydrocarbons (PAHs) in fine (PM2.1) and coarse (PM2.1-10) particles at suburban and city site during an autumn haze episode in Nanjing.PM10 samples were collected from Nov.1,2009 to Nov.14,2009.Filter samples were extracted by using Soxhlet and analyzed by using a gaseous chromatograph/mass spectrometer (GC-MS).Sixteen PAHs were measured at day and night of suburban and city site in this study.The results show that the concentrations of particles could be as high as 579.55 and 573.43μg/m-3 at suburban and city site during the haze episode,it was 3-4 times higher than normal days and the proportion of fine particles in the haze episode was also higher than normal days; the varies of concentration of PAHs were in accord with the concentration of particles.The concentrations of particles and PAHs at night were higher than in the daytime both at city and suburban site during the haze episode; the main kinds of PAHs in particles were the high-molecular-weight PAHs which make up approximately 80% of the total PAHs no matter in normal days or haze episode.It also turns out that wet removal mechanism has strong scavenging ability for pollutants,especially for the fine fraction; the spectral distribution of PAHs was the transfer of coarse fraction to fine fraction and this phenomenon was most obvious at night at city site,which indicates that the emission sources and the condition of boundary layer play important roles in the distribution and concentration of PAHs; the concentration of CAN-PAHs is relatively higher at both sampling sites and periods,the highest proportion of CAN-PAHs appear at the night of city site,it was as high as 52% of total PAHs,it is higher risk exposures for the people in Nanjing.