南京气溶胶水溶性离子粒径分布及其随高度的变化

Size Distribution of Water Soluble Ions in Aerosol and Its Variation with Height in Nanjing

2009年1月对南京市河西生活区距地面1．5、54和80m3处同步进行了大气颗粒物采样，并用离子色谱对样品进行了分析。结果显示，随着高度的增加，PM10和PM2.1的质量浓度逐渐降低，而总离子浓度随高度增加而增大。气溶胶中最主要的3种水溶性离子分别为N03、SO4 2-、Ca2＋，且3个高度的NO3-与SO4 2-浓度之比均大于1，表明该生活区移动排放源已经成为大气气溶胶离子的主要来源。3个高度处各离子粒径分布规律为：SO4 2-、NO3-、K＋在0．43-1．1um出现峰值；Ca2＋、Mg2＋、NO2-在4．7～5．8um出现峰值；Na＋、Cl-、F-在0．43～1．1um和4．7～5．8um出现双峰。

Atmospheric particles were simultaneously collected at the heights of 1.5 m,54 m and 80 m in Hexi downtown of Nanjing in January 2009. The samples were then analyzed by Ion Chromatograph. The results showed that, with increase of height, mass concentration of PM10 and PM2.1 both gradually decreased, whereas the total concentration of ions increased. The three most prominent water soluble inorganic ions are NO3-, SO4 2- and Ca2＋. Moreover, the concentration ratio of NO3- versus SO4 2- at the three heights were all larger than one, which indicated that the mobile emission sources had become the major source of atmospheric aerosol ions in this district. The size distribution of each type of ions at the three heights were ： SO4 2- , NO3- and K ＋ peaked at 0.43-1. 1 um ; Ca2 ＋ , Mg2 ＋ and NO2 peaked at 4. 7-5.8 um ; Na＋ , Cl- , F-, K ＋ peaked at 0. 43-1. 1 um and 4.7-5.8 um.