| The expansion of cities and the increase in population have caused problems,such as energy consumption and pollutant emissions.Since the air quality monitoring standards were updated in 2013,fine particulate matter PM2.5 in the air has been the primary pollutant in air pollution in my country.Many studies have shown that urban green space can reduce PM2.5.According to the distribution of air quality monitoring points,city scale,climate characteristics,vegetation types,nine cities,including Suzhou,Hangzhou,Hefei,Wuhu,Nanchang,Jiujiang,Wuhan,Changsha,and Yueyang,were selected as the research objects.Taking nine cities in the middle and lower reaches of the Yangtze River as examples,the innovative use of morphological spatial pattern analysis(Morphological Spatial Pattern Analysis,MSPA)to compare and analyze different urban green space pattern elements.Quantitative analysis of different urban green space pattern elements and their PM2.5concentration,and an optimization strategy for urban green space pattern reduction of PM2.5 concentration is obtained.The main results of this research are as follows:(1)According to the PM2.5 concentration of control points and urban sites in each city,the temporal and spatial characteristics of PM2.5 distribution in each city are obtained.In terms of time,the PM2.5 concentration presents a "U"-shaped pattern,and it decreases from January to June.Trend,July to August is the lowest value,September to December shows an upward trend.(2)Based on the analysis of the green space pattern of 9 urban areas,the seven elements of MSPA are divided into point and area patterns,boundary patterns,and corridor pattern element analysis.Among the point and surface pattern elements,the core proportion ranges from 28.16% to 51.6%,and the isolated island elements proportion ranges from 8.69% to23.63%;among the boundary pattern elements,the marginal proportion ranges from 20.65%to 28.32%,and the pore proportion ranges from Among the corridor pattern elements,bridging elements accounted for 4.28% to 13.54%,loop elements accounted for 1.75% to3.61%,and branch lines accounted for 9.23% to 18.67%.Clustering the spatial pattern elements can be divided into three types of cities: 1)Core-dominant type,including Jiujiang and Hefei 2)Core edge and heavy-duty cities,including 6 cities including Hangzhou,Changsha,Wuhan,Suzhou,Nanchang,and Yueyang,3)Isolated island-dominant cities,including Wuhu.(3)Correlation analysis of PM2.5 concentration and urban green space pattern elements shows that the core and pores are the pattern elements that affect the PM2.5concentration the most.When the core proportion reaches 8%,the reduction trend of PM2.5concentration will increase.The increase in the proportion of island elements is not conducive to the reduction of PM2.5 concentration.Based on the analysis results,three strategies are proposed for the planning of urban green space patterns: 1)Increase the area of core patches,integrate island elements,and reduce the degree of patch fragmentation;2)Increase the proportion of border patterns,increase patch complexity,and optimize core patches Block boundary shape;3)Enhance the elements of corridor pattern,reduce the fragmentation of green space pattern,and strengthen the internal connection degree of green space pattern.(4)The overall connectivity of the green space is significantly related to the PM2.5concentration.The higher the connectivity of the green space,the lower the PM2.5concentration.Based on the analysis results,the green space connectivity optimization strategy is proposed: Build urban green corridors to ensure the core position of the largescale patch,relying on existing resources,strengthen the internal connection of the green space in the urban area,and enhance the overall connectivity of the green space. |
