一次天气过程影响中国城市空气质量的空间统计分析

An Spatial Statistical Analysis on the Air Quality Change in Multi-Cities System of China with Once Weather Process

城市空气质量具有区域扩散性,基于单个城市为单元的空气质量研究具有较大的局限,有必要从区域角度来分析不同城市之间的空气质量的内在联系,为区域空气质量管治提供有效的依据。选择一次冷空气过程时段,采用空间统计方法,对中国大陆86个城市在该时段的空气污染指数进行分析。结果发现,1) 当没有发生全局性影响的天气过程时,中国各城市的空气污染指数存在空间自相关性,且这种空间自相关性随着城市间距离的增大而减小,这种现象可以理解为距离较小的城市之间,其污染行为和扩散条件相对比较相似。2) 当具有全局性影响的冷空气行进时,会改变部分城市的污染扩散条件,从而可能使得这种空间自相关性得以保持。3) 在冷空气过后,所有原先空气质量较差的城市的污染得到扩散,打破了原有的空间自相关性。这证明城市空气质量的跨界溢出是客观存在的。

Due to the spatial spreading of Air pollution, it is necessary to discuss the air quality from the view of the multi-urban system, rather from the single city. The research on the cross board environ-mental spillover of the air quality among different cities is helpful for controlling the regional air pollution. Data from the China Meteorological Administration reported high values of API in 86 Chinese cities during a cold air process. With the cold air passing, the spatial pattern of the air quality changed. Based on the facts, the spatial auto-correlation analysis is adopted. It showed that before the cold air came, there existed spatial auto-correlation of API among the eighty six cities. Moreover, the degree of correlation was influenced by the geographical distance among the cities, the weaker the correlation, the farther the distance. In other words, the cities closer one another were similar on the pollution behaviors and the condition of pollution spreading. However, when the cold air arrived, which was strong enough to affect all cities in the region, the condition of air pollution spillover changed partly. As a result, the original spatial correlation is still maintained. After the cold air passed, the original situation was destroyed. The pollution materials in those ci-ties, of which are serious in air pollution, spread around. It means that the air quality of urban has the cross board spillover.