Characterization of gases and water soluble ion of PM2.5 during spring and summer of 2006 in Xi''''an
西安市春夏季气体及PM2.5中水溶性组分的污染特征

The investigation of PM_(2.5) aerosols using a portable mini-volume sampler was conducted between May 22 and September 22,2006,in high-tech zone,Xi'an.Meantime NH_3 gases were also sampled using passive Ogawa sampler.Water soluble ions(WSI) and NH_3 concentrations were analyzed using an ion chromatogram(IC) analyzer.Integrating these data with SO_2 and NO_2 mass concentrations,the characteristics and sources of WSI of PM_(2.5) in spring and summer in Xi'an were studied.The results indicated that WSI in spring and summer was mainly composed of SO~(2-)_4,NO~-_3 and NH~ _4,accounting for 21.68%,7.52% and 5.62% in mass,respectively,and the PM_(2.5) in spring and summer in Xi'an were generally acidic.SO_2 mass concentrations were poorly correlated with SO~(2-)_4,NO~-_3 and NO_2,indicating that sulfate,nitrite,and ammonium in Xi'an are of different origins.