大气PM2.5载带重金属的区域污染特征研究

PM_2.5载带的重金属元素对人体健康具有重要影响，为了明确PM_2.5中重金属的污染水平以及区域性污染特征，收集并总结近30年中国不同地区大气重金属污染的研究成果，对PM_2.5载带的As、Zn、Cr（Ⅵ）、Pb、Cd、Mn以及Ni等7种重金属元素的区域污染特征进行分析.研究显示:①我国对部分重金属〔Pb、Cd、Hg、As、Cr（Ⅵ）〕的质量浓度增设限值规定，但未涉及Ni和Mn等有毒重金属.②全国范围来看，不同背景点PM_2.5中重金属质量浓度相差较大，自然背景点重金属质量浓度低于乡村背景点和近城市背景点的40.7%~97.6%.大气PM_2.5重金属区域污染高值区主要集中在华北、华东、华南等经济发达地区.《大气污染防治行动计划》等政策的实施使PM_2.5中重金属质量浓度明显下降，2013年前（1980—2013年）与2013年后（2013—2018年）相比，全国大气PM_2.5中ρ〔Cr（Ⅵ）〕、ρ（Ni）、ρ（Pb）、ρ（Mn）和ρ（As）均有所下降，但ρ（Zn）、ρ（Cd）略有上升.③典型城市PM_2.5中重金属污染特征各不相同.北京市需考虑Cd、As排放情况，强化对燃煤源的管控；上海市和广州市应关注Cr（Ⅵ）和Ni的排放，加严工业污染治理，加强对港口的排放管控.研究显示，对于大气颗粒物中重金属的治理，建议进一步关注对As、Cr（Ⅵ）排放的控制，同时对不同区域的大气重金属污染需要选择差异化的污染控制措施. 

Regional Pollution Characteristics of Heavy Metals in PM2.5

The heavy metals in atmospheric particulate matter have important effects on human health. In order to understand the pollution levels and the regional pollution characteristics of heavy metals, this study collects and summarizes the research results of atmospheric heavy metal pollution in different regions of China in the past 30 years. Seven heavy metals including As, Zn, Cr(Ⅵ), Pb, Cd, Mn and Ni in PM_2.5 were collected and analyzed. The results show that: (1) The national standard concentration limits for some heavy metals (Pb, Cd, Hg, As, Cr(Ⅵ)) have been set, but Ni and Mn are involved. (2) The background concentration of heavy metals in PM_2.5 of China varies greatly from site to site. The concentrations of natural background sites are 40.7%-97.6% lower than those of rural and near-city background sites. The regions with high levels of heavy metals in PM_2.5 are mainly concentrated in economically developed areas, such as North China, East China, and South China. The implementation of the National Air Pollution Prevention and Control Action Plan in 2013 has significantly reduced the concentration of heavy metals in PM_2.5. The pollution levels of heavy metals before and after 2013 are compared. ρ(Cr(Ⅵ)), ρ(Ni), ρ(Pb), ρ(Mn) and ρ(As) in PM_2.5 all decrease, but ρ(Zn), ρ(Cd) slightly increase. (3) The characteristics of heavy metal pollution in PM_2.5 in typical cities are different. In Beijing, the emission sources of Cd and As should be controlled. More attention should be paid to the control of Cr(Ⅵ) and Ni in Shanghai and Guangzhou. The study shows that to control heavy metals in atmospheric particulates, it is recommended to pay more attention to the emission control of As and Cr(Ⅵ). Different pollution control measures should to be considered for difference regions of atmospheric heavy metals.