Characteristics of PAHs in the atmosphere in winter and summer in the urban and suburban of Fuzhou

Air samples from four sampling sites in urban and suburban in Fuzhou were collected by Hi-vol air samplers in winter and summer in 2010,and concentrations of PAHs were analyzed by GC-MSD.The total(particle and gas phase) PAHs concentrations in ambient air were in the range of 115.45-187.76 ng·m-3in winter and 45.55-59.20 ng·m-3 in summer.PAHs in the gas phase were significantly higher than those in the particle phase,and PAHs in winter were higher than those in summer.No significantly difference was found between urban and suburban,with little higher PAHs in urban in winter and lower PAHs in summer.The ratios of PAHs in the gas phase to particle phase in summer were significantly higher than those in winter.The 2-4 rings PAHs were the dominant components in the gas phase while PAHs in the particle phase were dominated by 4-6 rings.The 3 rings PAHs were the dominant components in the gas phase in winter while 3 and 4 rings in summer.No significantly seasonal trends of PAHs components were found in the particle phase.The toxic equivalence factor(TEF) assessment showed that the pollution of PAHs in Fuzhou city was at a low level.Source analysis indicated that PAHs mainly came from combustion and diesel fuel was the predominant fuel in Fuzhou.