南京市大气气溶胶中部分无机离子的粒径分布

Size Distribution of Inorganic Ions of Atmospheric Aerosols in Nanjing

将气溶胶粒子(粒径Dp为0～8 5μm)分为8级,对各级粒子中的无机离子(NH+4,SO42-,NO3-,Cl-和F-)进行分析测定。结果显示,Cl-,F-和NO3-较多地分布在粗粒子中,而SO42-和NH4+则更多地分布在细粒子中。在质量浓度分布函数图上,NH4+,Cl-,F-和SO42-是双峰分布,NO3-没有表现出粒径分布的规律。SO42-对细粒子的酸碱度影响较大,其质量浓度与NH4+有较好的相关性。细粒态的NH4+大多以(NH4)2SO4形式存在。

Particulate matter of aerosol was cut off into eight stages (particle diameter ranges 0 and 8.5 μm), and inorganic ions (NH_4^+, SO_4^(2-), NO_3^-, Cl^-, F^-) of every stage were analyzed. The results show that Cl^-, F^- and NO_3^- dominate in the coarse particles, while SO_4^(2-)and NH_4^+ are mostly in the fine particles. From the figure of mass concentration, the size distribution of the NH_4^+, Cl^-, F^- and SO_4^(2-) show dimodal nature, while NO_3^- shows non-modal nature. SO_4^(2-)mostly effects acidity of the fine aerosol. SO_4^(2-) is correlative with NH_4^+, and NH_4^+ is mostly in the mode of (NH_4)_2SO_4.