Study on reduction characteristics of PM2.5 and PM10 in urban parks based on DSM:a case study of Nanchang People's Park
[Objective]Air particulate matter such as PM2.5 and PM10 are the primary pollutants in urban air,occupying a dominant position in urban air pollution.Understanding the reduction characteristics of PM2.5 and PM10 in urban green spaces under fixed external sources can provide favorable basis for controlling air particulate matter and alleviating air pollution in cities.Most of the current research on air particulate matter quantify the impact of spatial structure and vegetation type on air particulate matter through point measurement,however,there is little research on the impact mechanism of PM2.5 and PM10 on the spatial scale of urban green spaces under fixed external pollution.[Method]Taking Nanchang People's Park as an example,this study combines DSM and geostatistics to explore the spatial gradient effect and spatial structure type difference of urban parks in blocking exogenous pollution.The Kriging interpolation method was used to visually simulate its spatial distribution characteristics.Arcgis and R language were used to analyze the concentration differences of PM2.5 and PM10 in different spatial structures.[Result]The concentrations of PM2.5 and PM10 in the park had a consistent spatial distribution trend,with fixed external points as the core.The concentration decreased significantly with the increase of distance,and the reduction efficiency was the highest in the middle(about 150-220 m from the external point),which was about 7.5 times of the average reduction value of PM2.5 and 3.8 times of the average reduction value of PM10.PM2.5 and PM10 are influenced by multiple factors.They were significantly and negatively correlated with air temperature and distance(the dominant factor),as well as significantly and positively correlated with relative humidity.Moreover,there are differences in the response characteristics of PM2.5 and PM10 to different factors.The reduction and diffusion effects of different green space structures on PM2.5 and PM10 in urban parks were significantly different.The concentration of PM2.5 and PM10 in different areas ranked as follows:water>square>forest>lawn,with PM2.5 being more significantly affected;In addition,due to the coupling effect of various factors and green space structure,the distribution of PM2.5 and PM10 in some areas was abnormal.[Conclusion]With fixed external sources as the core,the concentrations of PM2.5 and PM10 show a highly significant gradient decreasing trend with distance,and the highest reduction efficiency is observed in the central region.The concentrations of PM2.5 and PM10 are significantly correlated with relative humidity,while they are significantly and negatively correlated with air temperature and distance.Among them,PM10 has a more positive response to distance and relative humidity,while PM2.5 is significantly affected by air temperature;On the basis of distance variation,the differences in the reduction and diffusion effects of different urban green space structures on PM2.5 and PM10 lead to local distribution differences.
PM2.5PM10resistance and control of air particlesurban green spacedigital surface modelgeostatisticsNanchang
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