【摘要】 北京市降尘在风沙天气中占有显著地位。本文依据降尘的最新资料—1988年4月的一次大风降尘重矿物分析资料与北京市各类沙土的地矿背景值比较,差异很大,推测为外来;又重新分析了“无风降尘”的微量元素分析资料,认为其主要组成为工业、交通的排放物。更多还原

【Abstract】 Dustfall deposits hold an important place in the sand-bearing wind weathers in Beijing region. According to the latest data,i. e. heavy mineral analytical data of dustfall deposits collected in a gale of April, 1988 and the comparative results of mineralogical background values in various sandy soils it is assumed that there might be an external origin of dustfall deposits. From the analytical results of trace elements in windless days it follows that their chief constituents were fine dusts derived from industries and transport network.更多还原