Spatial-temporal Characteristics Of PM_2.5 And Pollution Risk Assessment In China

Airborne fine particulate matter(PM_2.5)pollutes the air.And the primary pollutant of many cities is PM_2.5 which affects people's physical and mental health as well as production and life in China.It has gradually become a focus of social concern in recent years.As one of the main pollutants in the atmospheric environment,addressing the seriousness of the PM_2.5pollution in China,the spatial distribution differences and the complexity of the influencing factors,this paper aims to reveal the characteristics of the spatial-temporal distribution and influencing factors in China.So,the study combines geographic information technology,geographic science,spatial statistical methods and use a combination of quantitative and qualitative methods to assess the pollution risk of PM_2.5 by means of data-spatial statistical analysis methods-Geodetector-spatial decision support.This assessment was conducted to analyze the influencing factors of PM_2.5.5 pollution.Firstly,based on the concentrations of PM_2.5 in 348 cities from 2015 to 2017 in China,this paper analyzes the trend of temporal and spatial distribution of PM_2.5 in China in the past three years from 2015 to 2017 and uses 2015 as the typical year,use Spatial Autocorrelation?Global Moran's I?and local autocorrelation?Local Moran's I?method to explores its Spatial-temporal variation and spatial distribution pattern and spatial agglomeration characteristics from the three time scales of year,season and month.Secondly,it uses Geodetector to detect the influence factor of PM_2.5.Finally,it uses spatial decision support which contains Wighted Linear Combination?WLC?and Ordered Weighted Average?OWA?to assess the risk of PM_2.5pollution.Through comparison and analysis,the main factors of PM_2.5 pollution will be obtained,and management suggestions will be proposed.The research results have certain theoretical significance for understanding the Spatial-temporal distribution of PM_2.5 and controlling PM_2.5 pollution in China.It is helpful to govern the scientific decision-making of PM_2.5 and predict its occurrence and development.At the same time,it has reference significance for the governance of other atmospheric pollution.This paper researches the Spatial-temporal characteristics of PM_2.5 in China and assesses the risk of PM_2.5 pollution.The main findings are as follows:?1?During the period of 2015²017,the year of 2015 was the worst year for PM_2.5pollution.?2?From the point of view of time,the PM_2.5 concentration was lower in summer and higher in winter.In the space,Hu Line and the Yangtze River are the dividing lines between the east-west and north-south directions,respectively.The concentration of the east area of Hu Line is higher than in the west,and the in the north area of the Yangtze River is higher than in the south.Contered on the North China Plain area,the high concentration area is moving southwards and northeastwards,showing the trend of southward retreat to the north and northward retreat to the south.?3?The concentration of PM_2.5 is spatially autocorrelation,and its spatial agglomeration feature is obvious.The hotspots are mainly concentrated in the North China Plain,spreading from this region to the middle and lower reaches of the Yangtze River,Cheng-Yu District and Northeast China.The cold spots are mainly concentrated in the southwest regions such as Yunnan Province,the western Sichuan Plateau,and so on,and the trend is from the area to the east and north.?4?In terms of influence factors,the influence of single factor on PM_2.5.5 concentration is less than the influence of factor interaction.The interaction of natural factors on the PM_2.5concentration is less significance than natural factors and Socioeconomic factors.The explanatory power of interaction which some climatic factors interact with socio-economic factors,is more than 40%.?5?The PM_2.5 pollution risk led by social and economic factors is high,with a wide range of distribution,and is obviously higher than the PM_2.5 pollution risk under the combined effects of natural factors and socio-economic factors,much higher than the risk of PM_2.5pollution led by natural factors.The Beijing-Tianjin-Hebei Urban Agglomeration has a higher risk of pollution due to population,urbanization,and frequent economic activities.The risk of PM_2.5 pollution in southwest China is relatively small,which is a function of topographic factors and socioeconomic activities in the region.Chengyu Urban Agglomeration is affected by the dual impact of economic development and basin topography,so the risk of PM_2.5pollution is relatively high.