为揭示我国城市PM(2.5)中重金属水平的总体分布,在文献调研的基础上,对24个省会城市PM(2.5)中重金属(包括类金属)数据进行分析和对比,阐述我国省会城市PM(2.5)中As、Cd、Cr、Cu、Ni、Pb和Zn的分布及累积差异,并探讨相关城市发展参数对重金属水平的可能影响.结果表明:(1)PM(2.5)中各元素平均浓度从高到低的顺序为:Zn〉Pb〉Cu〉Cr〉Ni〉As〉Cd,元素浓度分别为311、105、35.4、19.8、17.7、17.1、2.08 ng·m^-3,与土壤背景值相比,Pb和Cu较其他元素累积明显;与我国环境空气质量标准比较,78%的城市PM(2.5)中As浓度超过我国环境空气质量标准限值;(2)城市间PM(2.5)中重金属浓度变异度较大,总体上,广州PM(2.5)中重金属浓度较高,台北PM(2.5)中重金属浓度较低;(3)对于不同的金属元素,其高值区出现的区域不尽相同,总体而言,城市PM(2.5)中重金属的区域分布特征是:西北〉华中〉华南〉华北〉东北〉西南〉华东;(4)PM(2.5)中重金属浓度的季节分布呈现冬、秋季较高,春、夏季较低的特征;(5)城市发展对城市PM(2.5)中重金属水平有一定影响.
Distribution of heavy metals As, Cd, Cr, Cu, Ni, Pb and Zn in PM2.5 from some provincial capital cities in China and the potential impact of urban development parameters on heavy metal levels in PM2.5 were studied by analyzing and summarizing data for 24 provincial capitals from the published scientific literature. Result show that the annual average concentrations of the elements in PM2.5 follows the order of Zn〉Pb〉Cu〉Cr〉Ni〉As〉Cd, with average concentrations of 311, 105, 35.4, 19.8, 17.7, 17.1 and 2.08 ng-m-3, respectively. Comparing with the background values in soils, contents of Pb and Cu are higher than other elements. Comparing with the Ambient Air Quality Standard of China, the concentrations of As in PM2.5 in 78% of the study cities exceeded the limit value. Variations of heavy metals between different cities are considerably large with Guangzhou haveing the highest level and Taibei the lowest level. The element with highest concentration was different for each city. In general, the regional distribution of heavy metals in PMz5 is in the order of Northwest region 〉 Central China 〉 South China region 〉 North China region 〉 Northeast region 〉 Southwest region〉East China. The levels of heavy metals in PM2.5 in winter and autumn are relatively higher than those in spring and in summer; and urban development has potential influence on the concentration level of heavy metals in PM2.5.