衡阳市区空气颗粒物的污染特征研究

Research on the Pollution Characteristic of Atmospheric Particulate Matter in the Hengyang Region

2014年4~5月在衡阳市区四个典型的城市功能区设置采样点,共采集了47个大气样品,对空气颗粒物（ TSP、PM2.5）的污染状况进行调查,分析其中的重金属（ Pb、Cd、Cu、As、Hg）含量及其形态分布.结果表明,大部分采样点PM2.5浓度超过国家环境空气质量标准（ GB3095—2012）中的二级浓度限值,部分地段TSP浓度超标；空气颗粒物中重金属元素质量含量大小的顺序为：Pb＞Cu＞As＞Cd＞Hg,这些重金属元素更容易富集在细颗粒物PM2.5上；形态分析表明,As、Hg主要以残渣态存在, Pb、Cd、Cu则以可交换态和残渣态存在较多.

From April to May 2014,47 air samples were collected in four typical urban func_tional areas of Hengyang,to investigate the atmospheric particulate matter. The heavy met_als（ Pb,Cd,Cu,As,Hg） content and speciation in the sample had been analyzed. The results showed that the mass concentration of PM2. 5 in most sampling points exceeded the daily mean value of the ambient air quality standards（GB3095—2012）,the same with the mass concentration of TSP in some areas. The sequence of concentration levels of heavy metals in particulate matter was as followed：Pb〉 Cu〉 As〉 Cd〉 Hg. These heavy metals are easier to concentrate in the fine particle（ PM2. 5 ） . The results of speciation analysis showed that the main speciation of As and Hg are residue. The exchangeable speciation and residual specia_tion in Pb,Cd,Cu are more than other speciations.