Spatial And Temporal Pattern Of Dust In Changsha Urban Area And Analysis Of Influencing Factors

At present,the type of air pollution in our country has changed from coal smoke to the compound type,and regional atmospheric particulates not only cause damage to human health,but also affect the ecological safety,which is an important factor affecting people's life happiness.With the rapid development of urbanization in China,fugitive dust caused by construction and exposed ground has increasingly become the major source of the urban atmosphere particulates pollution.This paper takes the urban area of Changsha as the research object,considers flying dust as a pollution source and a particulate matter provider,and researches the time and space characteristics and influence factors of flying dust in the urban area of Changsha.The research is of great practical significance to the urban environment and physical and mental health of mankind,and provides data support for the pollution supervision and control of government and relevant departments of pollution supervision and control.The main contents of this paper are as follows:?1?Adopt the method of combining the extraction of high resolution remote sensing images with the estimation of emission factors to research the time and space patterns of flying dust source on the ground.According to the analysis results,it is found out that the land area of flying dust source of construction and soil generally present a trend of increasing first and then decreasing on the whole from 2014 to 2018.The interannual variation of the emission of particulate matter of flying dust source of construction is small,the variation of emission of particulate matter of flying dust source of soil is significant.The space variation presents that the emission of particles matter of flying dust source in the border area between Wangcheng District and Yuelu District is higher,and the emission in the central urban area and the western area of Wangcheng District is lower.The aggregate level of the emission of flying dust source is high and presents a characteristic of significant unbalanced distribution.?2?Based on the concentration data of PM_2.5 and PM₁₀ monitoring stations in Changsha from 2014 to 2018,and through time series analysis of these data,the results show that the annual average concentration of PM_2.5 and PM₁₀ in Changsha from 2014 to 2018 has a downward trend with time;On the space pattern,space interpolation method is adopted to reflect the distribution characteristics of pollutant concentrations in the urban area of Changsha in different years.The south of Wangcheng District,Furong District and Kaifu District are the areas with high concentrations of PM_2.5and PM₁₀.Based on the average annual variation trend of the emission of flying dust source and the concentrations of PM_2.5.5 and PM₁₀,it is found out that the variation trend of pollution emission of flying dust source and the concentrations of PM_2.5 and PM₁₀ are relatively consistent.?3?Principal component analysis and multiple linear regression models are adopted to analyze the influence factors of the flying dust in the city,and the factors can be summarized into four main factors including weather conditions,urban pattern,natural environment and emission intensity of flying dust source.Among these factors,weather conditions,urban pattern and emission intensity of flying dust source have a promoting effect on the flying dust.Weather conditions have a great impact on the concentration of PM_2.5 in the city and have a small impact on PM₁₀.Urban pattern also has an important influence on the flying dust in the city.However,natural environment has diffusion and dilution effects on the flying dust in the city.