The Coupling Relationship Between Urban Air Pollution Effect And Land Use Pattern In Nanning City

In the process of future urban development,ecological processes such as urban expansion and changes in water areas are expected to drastically change the pattern of global land use,which in turn may cause changes in the environment and the evolution of urban landscape patterns,thus affecting the sustainable development of human society.The resulting global land cover and land-use change(LUCC)may have a major impact on atmospheric composition,but due to the complex interaction of climate,carbon dioxide,air pollutants,and vegetation,the degree of impact and even the signs of impact Very uncertain,causing difficulties in accurately predicting future air quality.In this study,the Nanning city was used as the object.The GIS and remote sensing(RS)technologies were used to take Nanning urban remote sensing image of the second phase(2009 and 2013)respectively.The Erdas software was used to geometrically correct and crop the synthetic image.After processing such as image fusion,according to the land use/coverage characteristics within the study area(40799.28 hectares),the pre-processed synthetic images were divided into five types of land use types:construction land,bare land,cultivated land,water area,and green land.Fragstats software was used to calculate the landscape pattern index,thus analyzing the evolution of urban landscape pattern in Nanning.Using the phase 2 air quality monitoring data(monthly and annual average concentrations of N02,S02,and PM 10),the coupling relationship between urban air pollution effects and land use patterns in Nanning was discussed.Research indicates:(1)During the five years from 2009 to 2013,the area of construction land and bare land in the study area has increased significantly,while the area of cultivated land has been greatly reduced,and the area of water areas and green areas has also declined to varying degrees.Cultivated land is gradually transformed into construction land and bare land to be constructed.Broken small water bodies and green lands are occupied by urban construction.(2)In the five years,Nanning city has been at a high level of urbanization.The degree of fragmentation of landscapes and the degree of clustering of patches have increased.Small patches have merged or disappeared,and the heterogeneity of landscapes has decreased.(3)During the five-year period,the concentrations of sulfur dioxide(S02),nitrogen dioxide(N02),and concentration of inhalable particles(PM 10)in the study area were significantly distributed.Therefore,the annual average pollutant concentration did not change much at all monitoring sites.At the same time,in addition to sulfur dioxide,the concentrations of nitrogen dioxide and respirable particulate matter have been greatly increased.(4)The spatial distribution characteristics of S02 concentration and N02 concentration in 2009 and 2013 have significant correlation with land use/cover type(P<0.05),and have a certain coupling relationship.However,the spatial distribution of respirable particulate matter is not stable,and the relationship with land use/cover types is not significant.Among them,the concentration of S02 in construction land,water areas,and arable land is relatively high.This is related to the large number of pollution sources for construction land and industrial emissions in cities and towns.However,the absorption and purification capacity of sulfur dioxide in water bodies is weak;the nitrogen dioxide is used in construction lands and waters.Higher,which is related to the weaker absorption and purification capacity of pollution sources arid water areas;the lower concentration of sulfur dioxide and nitrogen dioxide on green land and bare land,which is related to the absorption and purification capacity of greenland vegetation and less bare land pollution sources;the concentration of respirable particulates The spatial distribution is not stable and it is caused by the strong influence of urban construction.(5)Within the study area,there was no significant correlation between the change of landscape spatial pattern and the spatial distribution characteristics of air pollution concentration(P>0.05).This is different from the existing research results.It may be that the study area is a non-industrial city.The level of air pollution is relatively low.