【摘要】 研究重庆地区大气颗粒物中金属元素的浓度水平、分布特征及来源,对认识重庆区域和城市大气污染状况和控制颗粒物的污染具有重要意义。该研究于2013年9月至2014年2月期间,利用美国Xact-625环境空气多金属在线监测仪对重庆大气中PM_2.5的23种金属元素进行了连续采样,对比分析了霾日与非霾日金属元素的污染特征。结果表明,雾霾天气下PM_2.5和其中的18种金属元素浓度较正常天气均有升高,其中K、Fe、Ca、Zn、Pb、Mn、Ba、As为PM_2.5中的主要无机污染物。重庆市灰霾期间秋、冬季主要金属浓度分别是非灰霾期的1.5².2和1.1¹.7倍。各金属元素浓度的逐时变化规律总体上呈现出"单峰"和"双峰"分布,秋、冬季霾日和非霾日的逐日变化规律大体一致,秋季Ca、Mn、As质量浓度高于冬季,可能受人为影响影响较大。因子分析结果表明,重庆市霾日PM_2.5中金属主要来源于土壤风沙、施工和道路扬尘,冶金化工,汽车尾气,燃煤燃油。其中Pb、Zn、As、Ba等富集因子较大,大部分来自人为排放。为研究空气污染物的区域尺度输送,该研究利用后向轨迹模型对秋、冬季两个典型污染时期的后向轨迹进行模拟,结果显示,由于污染气团的外来输送,本地燃煤燃烧、冶金化工等污染源贡献可能是以上区域及传输通道口和重庆本地源综合作用的结果。更多还原

【Abstract】 It is necessary to investigate the level,distribution and source apportionment of main metal elements in PM2.5 to understand the regional and urban air pollution and particle pollution control.A continuous measurement of 23 metals was been performed from September 2013 to February 2014 in Chongqing to obtain PM2.5.Comparative analysis of the pollution characteristics of these elements during the hazy days（HD） and non-hazy days（NHD） has been made.PM_2.5 and 18 kinds of metal elements in hazy days has increased than normal weather.The main contribution of metals in PM_2.5 were K,Fe,Ca,Zn,Pb,Mn,Ba and As.The autumn,winter principal mental concentration on the hazy days were 1.5².2 and 1.1¹.7 times higher than those on non-hazy days.Diurnal variation of the concentration of each metal element overall exhibit on the "unimodal" and "bimodal" distribution.The daily variation of autumn and winter haze broadly consistent with the non-haze days.The autumn concentration of Ca,Mn,As is higher than winter,likely influenced by anthropogenic influences.Enrichment factor（EF） analysis for the main elements showed that metal components from anthropogenic origins（Pb,Zn,As and Ba） were highly enriched in PM_2.5,especially in hazy days.Factor analysis of futher disclosed that PM_2.5 in Chongqing in hazy days mainly derived from soil dusts,emissions from construction industries,metallurgic emissions,and the combustion of fossil fuel.The enrichment factor of Pb,Zn,As,Ba,etc.are moslty from anthropogenic emissions.For the study of regional scale transport of air pollutants,this study use backward trajectory model to simulation the typical pollution autumn and winter period during the autumn and winter,simulation results showed,due to the external transport of contaminated air mass,the local coal-fired combustion,metallurgical and chemical pollution contribution may be the result of the combined action of above area,transmission access point and local source in Chongqing.更多还原