沙尘暴降尘对甘肃大气环境背景值的影响研究

通过近15年来发生在我国西北地区的较大沙尘暴个例,就沙尘暴对甘肃境内大气环境背景值的影响等问题进行了调查、分析和研究.使用降尘背景观测点的大气降尘资料和样品,统计、分析和研究了沙尘暴降尘在各地区的沉降量、分布范围、化学组分和粒度分布特征等问题.研究认为:沙尘暴不只是一种特异的灾害性天气,同时它还是一种跨地区的大范围大气污染现象;在无湿沉降机会时,它会被输送到很远的地方,所影响和污染区域也会更大;沙尘暴还会向下游地区输送有害物质,对生态环境造成潜在和长期的影响;沙尘暴降尘量在甘肃的分布是以河西走廊东部为中心,向大气环流下游地域扩散,形成一个自西向东南迅速递减的梯度分布状态.受沙尘暴降尘的影响,近15年来甘肃省大气自然降尘背景值总体水平呈上升趋势. 

The Research on the Effect of Sand Storm Dustfall on Air Environmental Background Value in Gansu Province

Through big sand storm cases in the western region in China in last 15 years, the effects of sand storm on the air environmental background value in Gansu province were investigated and analyzed. Using air dustfall data and samples at background sites, the quantity of dustfall, distribution scope, chemical composition and grain distribution characteristics, etc. of sand storm deposition at different areas were analyzed. It is found that sand storm is much more than a kind of special disastrous weather; it is also a kind of air pollution phenomenon covering different provinces. In case of no wet deposition opportunities, it can be transported to far away places, thus affecting and polluting large area. Sand storm can transport some hazardous matters to the downwind and leave potential and long effects on the ecological environment. The sand storm dustfall in Gansu is distributed with the core at the east of Hexi Corridor, disperses to the downwind areas, forming gradient distribution from the west to the southeast. Because of the influence of sand storm, the overall level of air environmental background value of dustfall is increasing in Gansu province in the last 15 years.