中文摘要：

采用单颗粒分析方法对2004年2～3月发生在北京的3次沙尘暴的样品中沙尘颗粒物的化学成分进行了测定.3次沙尘暴的反向轨迹图显示,它们主要来自于中国北部、西北部和蒙古的戈壁沙漠地区,且这些沙尘颗粒主要通过高空长距离输送到下游区域.使用带能谱的扫描电镜对481个沙尘颗粒进行分析,并根据成分特征,把这些沙尘颗粒划分为8种类型,主要类型有“富Si”、“富Ca”、“富S”、“富Fe”.将北京样品分析结果与呼和浩特、塔克拉玛干和敦煌的结果进行对比,结果显示,长距离输送的沙尘颗粒表面发生了SO2的非均相化学反应,导致部分颗粒局部的表面发生化学修改作用,且“富Ca”的碱性矿物为非均相化学反应提供了更有利的反应界面.

英文摘要：

Dust samples were collected from three Asian dust storms in Beijing during February and March 2004. The dust particles originated from the Gobi desert in northern and northwestern regions of China and Mongolia, were transported to downstream areas over the continent. 481 individual dust particles were analyzed and classified into 8 different classes using scanning electron microscopy with X-ray energy spectra. The major classes of dust particles were defined as follows ＂Si-dch＂, ＂Ca-rich＂, ＂S-rich＂, and ＂Fe-rich＂. The Al-S-Ca ternary plot and comparison with dust particles collected around Taklamakan, Hob.hot and Dunhuang, indicated that the dust particles were chemically modified during long range transport. The Ca-rich particles offered a favorable interface for heterogeneous chemical reactions with acidic gas SO2 emitted by anthropogenic sources. The heterogeneous chemical reactions involving SO2 led to the modification of parts of the surfaces of some dust particles.