甘肃河西地区大气沙尘成分及影响分析

Analysis of Atmospheric Dust Composition and Its Influence in Hexi Corridor,Gansu

河西地区是中国西北干旱区沙尘暴活动比较频繁的地区之一,由沙尘暴引起的较高浓度的TSP严重污染城市空气质量。1999—2001年监测资料表明,河西走廊城市空气中TSP含量年平均值在沙尘事件和非沙尘事件期间的比率约为4～8倍。通过对2001年冬春季13次沙尘暴特征的统计分析,表明该区沙尘暴的特征主要体现在以下几个方面：①沙尘暴持续时间在1～3 d之间;②沙尘暴过程中的主导风向为NNW、NW和WNW;③1 h平均最大风速约为15.0 m·s^-1,TSP最高含量约为62.53 mg·m^-3。沙尘颗粒表面的化学成分主要为地壳元素SiO2、Al2O3、Fe2O3、CaO、MgO、K2O、Na2O和TiO,而其中的微量元素Cu、V、Pb、Zn和As主要来源于工业尾矿及其他人为污染物。

Hexi Corridor is one of areas suffered from the highest frequency of dust storm activities in arid regions of northwest China. The high concentration of air TSP caused by dust storms from Hexi Corridor seriously pollutes cities, air quality. The monitoring data from 1999 to 2001 demonstrated that the annual average air TSP content of cities in Hexi Corridor areas during dust events was 4-8 times as that during nondust events. Based on the statistic analysis of the characteristics of thirteen representative dust storms, it was demonstrated that these dust events were characterized by ①The duration of these dust events was about 1-3 days;②The dominant wind directions in these dust events was NNW, NW, WNW;③1-hour average maximum wind speeds was about 15.0 m·s^-1 and the maximum TSP levels was about 62.53 mg·s^-3. The surfaces of dust particles contained mostly crustal element oxides, such as SiO2, Al2O3, Fe2O3, CaO, MgO, K2O, Na2O and TiO2, however, some microelements such as Cu, V, Pb, Zn and As may be contributed to anthropogenic sources such as industrial tailings and some polluted materials.