中文摘要：

应用场发射扫描电子显微镜和X射线能谱仪，研究了2005年4月北京市区2次热型沙尘天气PM10样品中矿物单颗粒的形貌、数量一粒度分布和化学组成．研究表明：沙尘天气样品中的矿物颗粒呈边缘锋利的不规则状；数量-粒度分布在1．0 ～1．5μm出现明显的峰值．根据X射线能谱的定量数据，将721个矿物单颗粒分为7类．沙尘天气样品中的矿物颗粒主要以硅铝酸盐和石英矿物为主，并且有富Ca颗粒出现．大部分颗粒是2种或更多种矿物的内部混合物．沙尘天气富Ca颗粒占矿物单颗粒总数的5．9％，主要以CaCO3以及硅铝酸盐或石英的混合物的形式存在；非沙尘天气样品中富Ca颗粒含量高达14．5％，其中约有一半来自人为源排放．单个矿物颗粒中Ca含量以及m（Ca）／m（Al）可以用来区分外来沙尘源与本地矿物颗粒．

英文摘要：

Field emission scanning electron microscopy （FESEM） and energy dispersive X-my spectrometry （EDX） were used to obtain the morphology, number-size distribution and chemical compositions of individual ＂mineral particles collected during the two dust storm episodes in April 2005 in Beijing. It was found that the mineral particles were generally sharp-edged and irregular in shape. Number-size distribution of mineral panicles exhibited a unimodal pattern with the peak in 1.0-1.5μm range. On the basis of the quantitative results by EDX analyses, 721 particles were classified into seven types. Most mineral particles collected during the two dust events were aluminosilicates and quartz following by calcium-rich particles. Most mineral dust particles were internal mixtures of two or more minerals. Ca-rich particles were detected in 5.9% of all the dust-storm particles, and most of them presented as mixture of calcite and aluminosilicates or quartz. The content of Ca-rich particles was as high as 14.5% in non-dust-storm （NDS） sample. About half of calcium-rich particles in NDS samples indicated anthropogenic emissions as a major source of calcium-rich particles during NDS event. The content of calcium and the mass ratio of calcium/aluminum could be used to identify local and non-local mineral particles.