兰州市冬季细颗粒中微量金属元素及无机可溶性离子来源分析

Source analysis of trace metal elements and inorganic water-soluble ions in atmospheric fine particles in Lanzhou during winter

通过对兰州市区4个在线大气监测点冬季细颗粒成分进行测定,测得微量金属元素和无机可溶性离子分别占细颗粒浓度的1%、52%。微量金属元素中Pb的检出量最高,占本文所测微量金属元素总含量的39.3%;无机可溶性离子含量最高的是SO2-4,其次为NO-3、Na+,分别占本文所测9种无机可溶性离子的23.3%、20.5%和19.7%。采用富集因子法与因子分析法对微量金属元素来源进行分析,结果表明,微量金属元素的来源为燃煤源、风沙土壤源、金属加工,燃煤源成因率最高,为61.2%;采用因子分析法对无机可溶性离子来源进行分析,结果表明,无机可溶性离子的来源为二次转化、人为排放、土壤源(包括风沙土壤尘和道路扬尘),土壤源成因率最高,为49.5%。

Data about the componential characteristics of atmospheric fine particles, collected in 4 different on-line air monitoring stations in Lanzhou in winter, show that the two groups, trace metal elements and inorgan- ic water-soluble ions, occupy 1% and 52% ,respectively of the amount of most fine particle samples in density. And among the trace metal elements, Pb possesses the highest detectable amount, 39.3% of the total. While in the inorganic water-soluble ions, SO^2-4 is the major component, occupying 23.3% of the total; NO3^- is in the next place, occupying 20.5% of the total; and Na^＋ accounts for 19.7%. To identify the sources of these ele- ments and ions, enrichment factor mathod and factor analysis method were employed. According to the results, the sources of the trace metal elements are coal burning （accounts for 61.2% of all sources） , soil dust, metal processing, etc. ; the main sources of the inorganic water-soluble ions are soil （accounts for 49.5% of all sources, including soil dust and road dust） , secondary aerosol, and anthropic discharge.