基于复杂网络及其模体的京津冀及周边城市PM_(2.5)污染空间关联

Spatial correlation of PM_(2.5) pollution in Beijing-Tianjin-Hebei and surrounding cities based on complex networks and their motif

近年来,随着污染治理和生态环境保护力度的加大,京津冀区域生态环境质量持续改善,但是以PM_(2.5)为特征污染物的大气污染问题仍然不容小觑。选取了2015年1月1日—2022年11月30日京津冀及周边31个城市的PM_(2.5)浓度数据,结合引力模型与皮尔逊相关指数,构建了京津冀及周边城市PM_(2.5)污染的空间关联网络,并对该网络的整体特征与模体季节变化进行了统计分析。结果表明:邢台、石家庄、邯郸3个城市的度值、中介中心性、接近中心性均排名前3,它们在该网络中处于核心位置,与多个城市存在较强的PM_(2.5)污染空间关联,对于控制PM_(2.5)污染的空间溢出具有较为重要的作用;模体的四季关联网络密度和平均度相差不大,但均较高,各城市间的PM_(2.5)存在较强的空间关联,其中在冬季网络密度最高,石家庄、邢台、衡水在模体四季关联网络中起着重要作用。对于在京津冀及周边城市PM_(2.5)污染空间关联网络中处于核心位置的城市,在加强自身PM_(2.5)治理的同时,应制定政策减弱其对相邻城市PM_(2.5)污染的空间溢出效应;根据不同季节模体的关联情况,制定相应的协同治理政策,加强对这些模体城市PM_(2.5)污染的协同治理,同时减弱它们之间的PM_(2.5)污染空间关联与溢出效应。

In recent years,with the increase of pollution control and ecological environmental protection,the quality of the ecological environment in Beijing-Tianjin-Hebei region has continued to improve,but the problem of air pollution with PM_(2.5) characteristics should not be underestimated.PM_(2.5) data of 31 cities in Beijing-Tianjin-Hebei and surrounding areas from January 1,2015 to November 30,2022 were selected,combined with the gravity model and Pearson correlation index,to construct a spatial correlation network of PM_(2.5) pollution in Beijing-Tianjin-Hebei and surrounding cities,and the overall characteristics of the network and the seasonal changes of the motif were analyzed statistically.The results showed that Xingtai,Shijiazhuang and Handan ranked top 3 in degree value,betweenness centrality and closeness centrality.They were at the core of the network and had strong spatial correlation with PM_(2.5) pollution in multiple cities,which played an important role in controlling the spatial spillover of PM_(2.5) pollution.The density and average degree of the four seasons correlation network of the motif were not different,but both were high.There was a strong spatial correlation between PM_(2.5) among cities,and the network density was the highest in winter.Shijiazhuang,Xingtai and Hengshui played an important role in the four seasons correlation network of the motif.For the cities in the core position of the spatial correlation network of PM_(2.5) pollution in Beijing-Tianjin-Hebei and surrounding cities,while strengthening their own PM_(2.5) control,policies should be formulated to reduce the spatial spillover effect of PM_(2.5) pollution on neighboring cities.According to thecorrelation of the motif in different seasons,corresponding collaborative governance policies should be formulatedto strengthen the collaborative governance of urban PM_(2.5) pollution of the motif,while weakening the spatialcorrelation and spillover effect of PM_(2.5) pollution between them.