成都城区PM_(2.5)中有害微量元素的污染特征

Characteristics of hazardous trace elements in PM_(2.5) in urban area of Chengdu

在2011年各典型季节月，采集成都城区的PM2.5样品，采用电感耦合等离子体质谱仪（ICP—MS）分析获取32种元素浓度，对其中9种有害元素浓度、富集程度及可能来源进行分析．结果表明，有害元素Pb、Mn、As、Cr、Sb、Cd、Se、Ni和C0的年均浓度分别为（171．7±86．2）、（66．4±36．7）、（19．8±11．1）、（9．2±5．0）、（6．5±4．2）、（3．5±1．9）、（2．7±1．2）、（2．5±1．6）和（0．5±0．3）ng·m-3．绝大多数样品中As浓度超过世界卫生组织和中国环境空气质量标准的参考限值．元素se、cd、sb、Pb和As有明显的富集现象，富集因子均值范围在492～5340．受土壤尘的影响，所有元素的富集因子在春季较低．因子分析结果进一步表明PM2.5中有害微量元素主要来自机动车、燃煤以及金属冶炼等人为来源．

Daily PM2.5 samples were collected during the typical month of each season of 2011 at an urban site of Chengdu. 32 elements were detected in PM2.5 by ICP-MS, among which there were 9 hazardous elements. The concentrations, enrichment factors, and possible sources of the 9 elements were analyzed in this study. The annual average concentrations of Pb, Mn, As, Cr, Sb, Cd, Se, Ni, and Co were （171.7 ±86.2）, （66.4 ±36.7）, （19.8 ±11.1）, （9.2 ±5.0）, （6.5 ±4.2）, （3.5±1.9）, （2.7±1.2）, （2.5 ±1.6）, and （0.5±0.3） ng m-3, respectively. The As concentrations in most of the collected samples exceeded the guideline values provided by WHO and Chinese ambient air quality standards. High enrichment factors of Se, Cd, Sb, Pb, and As were found, ranging from 492 to 5340. Relatively low enrichment factors were observed for all the hazardous elements during spring, since the ambient aerosol was significantly affected by soil dust.The results contributed smelting. of the factor analysis further revealed that these hazardous by anthropogenic sources such as motor vehicle emissions, coal elements were mainly combustion, and metal