天津市PM2.5中水溶性离子组分特征

摘要

To investigate the characteristics of water-soluble ions in PM2.5,47 PM2.5 samples were collected from Aug to Dec,2006in Tianjin.The average concentration of PM2.5 was 165.90 μg/m3,which was 3.7 times over the EPA standard (35μg/m3).Water-soluble components including SO42-,NO3-,NH4+ and Cl-were dominant in PM2.5,accounting for 88.6％ of total inorganic elements.For each ion spesies,different seasonal varieties were displayed.High linear correlation between NH4+ and NO3-was obtained,with a coefficient of 0.795.The sulfate oxiding rate (SOR) and nitraite oxiding rate(NOR) were 0.16 and 0.23,both of which were higher in Aug than those in the other months during the monitoring period,which showed an significant activity of SO2transformation in summer.%2006年8-12月连续采集PM2.5样品,分析其中水溶性无机离子浓度特征.结果表明,采样期间,天津市PM2.5日均浓度均不同程度超过美国EPA日均浓度标准(35μg/m3)；SO42-、NO3-、NH4+和CI-为无机离子的主要成分,占全部无机离子的88.6％；各离子均表现出不同季节变化特征.对NH4+和NO3-、SO42-进行相关性分析发现,NH4+和NO3-相关性最好,相关系数为0.795.SOR和NOR的平均值分别为0.16和0.23,均为8月最高,表明前体物二次转化夏季最明显.