城市化对空气污染人群暴露贡献的定量方法研究

短期快速城市化引发一系列生态环境问题,尤其是近年来以细颗粒物(PM_(2.5))为代表的城市与区域空气污染问题。人群的污染暴露一方面是因为污染区范围的扩张,另外一方面则归因于城市化引发的人口迁移,目前的研究重点关注于前者的贡献,而忽略了后者的贡献。因此,建立了城市化对空气污染人群暴露贡献的定量方法,并选取我国PM_(2.5)污染最为严重的京津冀城市群开展了实证研究,通过利用2000、2005、2010、2015年PM_(2.5)浓度和人口栅格数据以及人口自然增长率数据,定量评估了城市化引发的人口迁移对空气污染人群暴露的贡献。研究结果显示:(1)京津冀地区受污染影响面积和人口变化显著,造成大量的人口暴露于PM_(2.5)污染。(2)城市化引发的人口迁移与自然增长贡献率方面:总体上,2000—2015年,京津冀城市群总的人口迁移贡献率为48%,北京市和天津市总的人口迁移贡献率分别为94%和88%,而河北省污染总的人口迁移贡献率为-32%。其中在污染保持区,北京市和天津市的人口迁移贡献率均接近100%,而河北省的迁移贡献率为-26%,尤其在2010—2015年,河北省衡水市的人口迁移贡献率达到-6613%;在污染新增区,北京市和天津市的人口迁移贡献率分别为86%和84%,而河北省污染的人口迁移贡献率为-757%。本研究建立了定量化的方法揭示了城市化在空气污染人群暴露中的定量贡献,为科学引导城市化发展提供了定量的手段,为合理规划京津冀城市群地区的人口流动与空气污染奠定了数据基础。

Method for quantifying the contribution of urbanization on population exposure to air pollution

Rapid urbanization has negative effects on the ecological environment, especially the air pollution in some areas of China, where the air has been widely polluted by the major pollutant known as fine particulate matter (PM_2.5) in recent decades. The population exposure in the contaminated area is generally due to the expansion of the contaminant''s area, but is also highly attributed to the population migration caused by rapid urbanization. In this study, we established a quantitative model for evaluating the contribution of urbanization on the population exposed to air pollution, and selected the Beijing-Tianjin-Hebei urban agglomeration, which has been suffering the most severe PM_2.5 pollution in China and undergoing rapid urbanization. By using PM_2.5 concentration, population raster data, and population natural growth rate data from 2000 to 2015, we quantitatively explored the contribution of urbanization on the population exposed to air pollution. The results showed that:(1) the Beijing-Tianjin-Hebei area affected by pollution and population changed significantly, resulting in a large number of people exposed to PM_2.5 pollution. (2) Contribution of population migration and natural growth caused by urbanization were varied:in general, the total population migration contribution rate, which is the percentage of migrated population in the total increased population that exposed to PM_2.5 pollution, of the Beijing-Tianjin-Hebei urban agglomeration was 48%, the total population migration contribution rate of Beijing and Tianjin were 94% and 88% respectively, and that of Hebei Province was -32% from 2000 to 2015. In the continuously polluted area, the contribution rates of population migration in Beijing and Tianjin were close to 100% in 2000-2015, while the contribution rate of migration in Hebei was -26%; in Hengshui City, Hebei Province, the contribution rate of population migration was -6613% in 2010-2015. In the areas into which pollution expanded, the contribution of population migration in Beijing and Tianjin were 86% and 84% respectively, while the contribution rate of population migration in Hebei province was -757% in 2000-2015. This study establishes a quantitative approach to reveal the quantitative contribution of population exposure to air pollution caused by urbanization.