Shi Zong-Bo, He Ke-Bin, Chen Yan-Ju, Yang Fu-Mo, Zhang Jie, Liu Yan, Ma Yong-Liang
Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China.
Huan Jing Ke Xue. 2008 Mar;29(3):551-6.
The purpose of this study is to investigate the effect of fog processes on the physical and chemical properties of aerosol particles in an urban atmosphere. Atmospheric particles were collected in the urban atmosphere of Beijing during fog and non-fog episodes. The morphology, size and elemental composition of individual particles were characterized using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDX). EDX analysis showed that elongated particles were composed of Ca-K-S or Ca-S, and most sub-round particles contained sulfur. Large amounts of elongated and sub-round particles were identified in the samples collected during fog episodes, and they were rarely detected in the samples collected during non-fog episodes. This suggests that the high relative humidity in the fogs facilitated the formation of elongated and sub-round particles. Number concentrations of particles larger than 0.2 microm were about 5 to 8 times higher during the fog episodes. In addition, a new mode around 0.4 microm appeared in number size distribution of particles during the fog episodes. These results indicate that heterogeneous reactions in the fogs could greatly change the chemical and physical properties of particles.
本研究的目的是调查雾过程对城市大气中气溶胶颗粒物理和化学性质的影响。在北京城市大气的雾天和非雾天期间采集大气颗粒。使用配备能量色散X射线光谱仪（EDX）的扫描电子显微镜（SEM）对单个颗粒的形态、大小和元素组成进行表征。EDX分析表明，细长颗粒由Ca-K-S或Ca-S组成，大多数次圆形颗粒含有硫。在雾天期间采集的样品中鉴定出大量细长颗粒和次圆形颗粒，而在非雾天期间采集的样品中很少检测到。这表明雾中的高相对湿度促进了细长颗粒和次圆形颗粒的形成。雾天期间粒径大于0.2微米的颗粒数浓度约高5至8倍。此外，雾天期间颗粒的数量粒径分布中出现了一个约0.4微米的新模式。这些结果表明，雾中的非均相反应会极大地改变颗粒的化学和物理性质。
