我国主要城市大气重金属的污染水平及分布特征

为研究我国城市大气中重金属(As、Cd、Cr、Mn、Ni和Pb)的污染水平及空间分布特征,通过CNKI、万方、维普、Science Direct、Google Scholar和PubMed等数据库检索并收集于2000—2014年10月期间发表的关于我国城市大气中重金属质量浓度的文献. 按照拟定的筛选标准筛选出59篇文献纳入分析研究,共涉及29个省(区、直辖市)53个城市,有效样本量大于5 863个. 其中,大气重金属质量浓度均以PM₁₀(采样测定结果)计. 结果表明:我国城市大气中ρ(As)、ρ(Cd)、ρ(Cr)、ρ(Mn)、ρ(Ni)和ρ(Pb)分别为27.7、14.1、60.9、220、37.5和290 ng/m3,均超过GB 3095—2012《环境空气质量标准》、欧盟《空气质量标准》和WHO(World Health Organization,世界卫生组织)《欧洲空气质量指南》中相应重金属质量浓度的年均标准限值或参考限值. 我国城市大气重金属污染主要分布在北方的京津冀、环渤海地区以及南方的珠江三角洲地区. 其中,Cd污染多分布在南方城市,Mn污染主要集中在华北和华东地区,As、Cr、Ni、Pb 4种重金属没有明显的空间分布特征. 大气中As、Cd、Cr、Ni、Mn和Pb的主要来源是化石燃料燃烧、金属冶炼以及交通废气排放等,其中煤炭等化石燃料的燃烧是其共同的污染来源. 

Concentrations and Distribution Characteristics of Atmospheric Heavy Metals in Urban Areas of China

Abstract: To investigate the characteristics of the concentrations and distribution of atmospheric heavy metals in urban areas of China, the literature on atmospheric heavy metal concentrations in Chinese cities published from 2000-2012 were searched and collected through databases including CNKI, Wanfang, CQVIP, Science Direct, Google Scholar and PubMed. Based on uniform criteria, 59 articles were selected for further analysis. The atmospheric heavy metal concentrations were reported in 53 cities of 29 provinces, and included more than 5863 valid samples. Atmospheric heavy metal concentrations were expressed by heavy metal concentrations measured by collected PM₁₀. The results showed that the average concentrations of As, Cd, Cr, Mn, Ni and Pb in urban areas of China were 27.7,4.1,0.9,0, 37.5 and 290 ng/m³, respectively. These values uniformly exceeded the annual reference or standard values of China''s National Ambient Air Quality Standard (NAAQS) (GB 3095-2012) as well as those of the European Union (EU) and the WHO. Concentrations of heavy metals were higher in the Beijing-Tianjin-Tangshan economic zone, the Bohai Sea region and the Pearl River Delta. The pollution of atmospheric Cr and Mn was serious in southern and eastern cities, respectively, but the other metals showed no obvious regional distribution characteristics. Fossil fuel burning, metal smelting and vehicle emissions were the main sources of atmospheric heavy metals. Coal combustion might be the most common source of atmospheric heavy metals.