北京大气气溶胶单个颗粒的化学表征

CHEMICAL CHARACTERIZATION OF INDIVIDUAL AEROSOL PARTICLES IN BEIJING

用安德逊分级采样器采集京郊三个点(北辛安、冷泉村和生态环境研究中心)的大气气溶胶颗粒.用扫描电镜/X射线能谱观察和分析单个颗粒的形貌和元素成分,对粗细颗粒分别进行了X射线物相分析.通过对颗粒的形貌、组分和化合物形态等的综合分析结果表明:细粒样品中常含有较多的铁或铵的硫酸盐及氯化铵.粗粒样品中则主要为矿物物质如石英、方解石、石膏、白云石和一些粘土矿物.圆形颗粒可能是煤的燃烧产物,许多不规则形的颗粒大多来源于土壤和砂石,也有些是钢铁工业的特征物质.

Atmospheric aerosol particles were collected by Anderson cascade impact sampler at three sites in Beijing. The morphological observation and composition analysis for individual particles were performed by scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (SEM/EDX). Phase analysis for coarse and fine particle fractions was carried out by X-ray diffractometer.Results indicate that the compounds observed in the fine fraction most frequently are iron/ammonium, sulfate and ammonium chloride. The coarse particle samples are pre-dominatly of mineral nature, e. g. quartz, calcite, gypsm, dolomite and some clay minerals. Some of the metallic compounds were originated from steel plant. It is deduced from this work that the spherical particles may be the products from coal combustion, and that the major irregular shaped particles might originate from soil and sandstone.