中国城市群臭氧时空分布特征分析

为揭示我国主要城市群近地面臭氧的时空分布规律,使用空气质量监测网站发布的2019年243个城市共计1215个站点的臭氧浓度数据对中国正在稳步建设的19个城市群的臭氧时空分布特征进行分析,结果表明:臭氧污染高发期主要集中在夏季6、7月份,春末秋初次之,冬季基本不发生污染.城市群100μg/m³以上的臭氧浓度占比变化趋势大致表现为不规则的“V”和“W”两大类.2019年我国19个城市群可明显提取出北部和南部两个浓度分布高值中心,分别出现在夏季和秋季,夏季根据污染严重程度又可将高值中心划分为两个层级.城市群臭氧浓度分布具有空间自相关特性,夏季热点区域与北部高值中心重合,秋季则与南部高值中心位置一致,此时冷点区域面积达到最大.由于臭氧污染成因的复杂性,不能简单以现有城市群等级划分结果对其进行分级管理,需要根据实际分布情况对不同城市群制定相应污染防控措施.

Spatial and temporal distribution characteristics of ozone in Urban agglomerations in China

In order to reveal the temporal and spatial distribution law of ozone in major urban agglomerations, the concentration data of 1215 stations in 243 cities of 2019, released by air quality monitoring website were used. The results showed that ozone pollution mainly occurred in June and July in summer, followed by late spring and early autumn, and almost no ozone pollution occurred in winter. The variation trend of ozone concentration with increases above 100μg/m³ in urban agglomerations roughly presented two categories of irregular "V" and "W". In 2019, two high-value concentration centers could be obviously extracted, which appeared in summer and autumn respectively. Further, the high-value concentration center in summer could be divided into two levels according to the severity of pollution. The concentration distribution of ozone in urban agglomeration showed autocorrelation characteristics:the hot spot area overlaping with the high value center in the north in summer, and being consistent with the high value center in the south in autumn, simultaneously, the area of the cold spot area reaching its maximum. Due to the complexity of the causes of ozone pollution, it is inappropriate to classify ozone pollution solely according to the existing circumstances of urban agglomerations classification. Formulating corresponding pollution prevention and control measures for different urban agglomerations according to the actual distribution is the key point.