顾及溢出效应的城市生态空间对PM_(2.5)污染的影响

Impact of Urban Ecological Space on PM_(2.5) Pollution Considering Spatial Spillover Effect

大城市是中国空气污染的重点治理区域,但现有研究聚焦于如何从源头上减少人为污染排放,鲜少关注如何通过优化城市生态结构以提升存量生态空间的环境效益,进而削减既定人为排放造成的空气污染。鉴于此,文章以空气污染较为严重且生态用地较为紧张的武汉市为例,利用高分辨率、高精度PM_(2.5)数据,结合土地利用转移矩阵与多元回归模型,探析了2000—2020年武汉市不同结构的城市生态空间对PM_(2.5)污染的削减作用及其空间溢出效应。研究结果表明:武汉市城市生态空间可以显著地削减PM_(2.5)污染,3期直接削减量分别为7.62μg/m^(3)、16.52μg/m^(3)和3.64μg/m^(3),直接削减作用是城市生态空间削减PM_(2.5)污染的主要渠道;武汉市城市生态空间在削减PM_(2.5)污染时具有显著的空间溢出效应,通过溢出效应产生的间接削减量分别为2.13μg/m^(3)、2.77μg/m^(3)和0.93μg/m^(3),远小于直接削减量,但也不容忽视;当生态空间规模一定时,不同结构的城市生态空间对PM_(2.5)污染的直接削减作用一致,而间接削减作用存在显著差异,相比于面状结构,线状生态空间对PM_(2.5)污染的间接削减作用更为明显,且随着规模的增加,差异越显著。该研究结果既可以丰富城市生态空间的环境效应研究视角,又可以为兼具经济发展和生态保护双重压力的大城市空气污染治理提供新思维。

Large cities are the key areas to control air pollution in China.However,existing research focuses on how to reduce anthropogenic pollution emissions from the source.Little attention has been paid to how to reduce air pollution caused by established anthropogenic emissions by optimizing the ecological structure of cities.In view of this,this study takes Wuhan city with severe air pollution and tight ecological land as an example.We use the team’s high-resolution and high-precision PM_(2.5)data inverted based on big data and artificial intelligence,combined with land use transfer matrix and multiple regression model,to explore the reduction effect and spatial spillover effect of urban ecological spaces with different structures in Wuhan on PM_(2.5)pollution in three phases of 2000,2010,and 2020.The research results indicated that:the urban ecological space in Wuhan can significantly reduce PM_(2.5)pollution,the direct reduction amounts for the three phases are 7.62μg/m^(3),16.52μg/m^(3)and 3.64μg/m^(3)respectively.The direct reduction effect is the main channel for reducing PM_(2.5)pollution in urban ecological spaces.The urban ecological space in Wuhan has a significant spatial spillover effect in reducing PM_(2.5)pollution,the indirect reductions generated through spillover effects are 2.13μg/m^(3),2.77μg/m^(3)and 0.93μg/m^(3),respectively,which are far less than the direct reductions,but cannot be ignored.When the scale of ecological space is fixed,the direct reduction effect of different urban ecological spaces on PM_(2.5)pollution is consistent,while the indirect reduction effect is significantly different.Compared to planar structures,the linear ecological space has a more significant indirect reduction effect on PM_(2.5)pollution,and the difference is more significant with the increase of scale.The results of this study cannot only enrich the research perspective of the environmental effects of urban ecological space,but also provide new thinking for air pollution control in large cities.