中国典型城市群PM2.5污染特征研究进展

为进一步梳理近年来我国城市区域大气PM_2.5污染防治方面的研究成果，基于我国31个城市PM_2.5污染现状，以城市群为视角，总结了京津冀城市群、长三角城市群与川渝城市群PM_2.5组成与污染特征，分析了PM_2.5及其含碳气溶胶、水溶性无机离子、地壳元素等的整体特征，并在城市群间进行对比分析.结果表明:①3个城市群的ρ（PM_2.5）高低顺序依次为京津冀城市群>川渝城市群>长三角城市群，长距离传输使PM_2.5污染成为京津冀城市群、长三角城市群与川渝城市群面临的共同问题.②3个城市群的PM_2.5中均以SNA和OC为主，尽管ρ（PM_2.5）水平有下降趋势，但个别污染物（如SNA）略呈上升趋势.③京津冀城市群与川渝城市群的ρ（OC）接近，并且均高于长三角城市群的80%，较高的ρ（OC）/ρ（EC）反映我国城市群普遍存在SOC污染.④各城市群PM_2.5监测网（如监测时间和采样方法）发展水平迥异，城市群之间的相互影响和传输机制尚不清楚.建议今后的研究向以下几个方面扩展:①对城郊乡村等大气背景点，以及水库、湖泊等地化循环的重要源汇区域开展研究.②针对同一区域开展采样时段更长且研究方法和分析手段上保持一致的研究.③借用国外经验公式时需考虑我国国情，对基础研究方法开展一系列优化，建立符合我国国情的标准化研究方法. 

Review of Pollution Characteristics of PM2.5 in Chinese Representative Megacities

In order to further summarize the research achievements in the prevention and control of PM_2.5 pollution in China''s urban areas in the past decade, we discuss the concentrations, sources and pollution characteristics of PM_2.5 in 31 cities in Beijing-Tianjin-Hebei Region, Yangtze River Delta and Sichuan-Chongqing Region. In particular, we compare mass concentrations and the PM_2.5 compositions of organic aerosols, water-soluble ions and crustal materials. The results show that:(1) The concentration of PM_2.5 followed the order of the Beijing-Tianjin-Hebei Region > Sichuan-Chongqing Region > Yangtze River Delta. Long-range transport made PM_2.5 pollution a common issue in the three regions; (2) The PM_2.5 was dominated by OC and SNA in the three megacity regions. Although the concentration of PM_2.5 had a decreasing trend year by year, the concentrations of some components, such as water-soluble ions, increased slightly; (3) The concentrations of OC in the Beijing-Tianjin-Hebei Region and Sichuan-Chongqing Region were comparable but were 80% higher than those of the Yangtze River Delta. High OC/EC indicated the prevalence of SOC in the three megacity regions; (4) PM_2.5 monitoring networks, including monitoring period and sampling methods, varied between the three regions, making interact-influence and transport mechanisms difficult to determine. Recommendations for future research include:(1) The need for further study in suburbs, rural and background sites. (2) The need for long-term studies in current urban monitoring locations and maintaining the consistency of research methods. (3) The need for standardizing research methods that are suitable for the current status of the atmospheric environment in China.