Analysis Of Spatiotemporal Differentiation And Influencing Factors Of PM_2.5 In Chinese Cities In 2020

Since the reform and opening up,with the acceleration of urbanization and steady development of industrialization,as well as the severe consumption of fossil fuels such as coal,oil,and natural gas,the air pollution in various cities in China has become increasingly serious,especially the large haze caused by fine particulate pollutants,which has become a highly harmful atmospheric environmental problem,And PM_2.5pollution in the atmosphere will have a certain negative impact on the environment and health that people rely on for survival.Because the increase of PM_2.5concentration is affected by natural factors,socio-economic factors and many other aspects,and the influencing factors of different seasons and months also have spatial heterogeneity differences.Therefore,this article uses methods such as Kriging difference and cold hot spot analysis in statistics and GIS technology to explore the spatiotemporal distribution pattern of PM_2.5in Chinese cities in 2020.Based on meteorological data,socio-economic data,etc.,the geographic weighted regression model（GWR）in GIS is used to analyze the reasons for the changes in PM_2.5concentration in various cities in China,and practical air pollution prevention and control suggestions are proposed.The main conclusions of this article are as follows:The average annual concentration of PM_2.5in 2020 was 32.73μg/m³,The average annual concentration of has decreased by nearly twice compared to 2014,which is related to a series of policies such as China’s strong ecological civilization construction,improving energy utilization efficiency,and optimizing industrial structure.In terms of time,the seasonal mean of PM_2.5concentration has a significant variation pattern of high in winter,low in summer,and centered in spring and autumn.From a monthly perspective,in August 2020,due to the fact that most cities in China are located in a monsoon climate zone,with frequent typhoons and concentrated precipitation,which have a certain dilution effect on atmospheric pollutants,August was the month with the lowest PM_2.5concentration of the year.However,in January,due to the low temperature,low precipitation,and centralized coal-fired heating in most cities in China,January was the most polluted month in China,Overall,within a year,the concentration of PM_2.5shows a U-shaped pattern of first decreasing and then increasing.The monthly and seasonal changes in PM_2.5concentrations in the seven major geographical regions of China in 2020 are basically consistent with the national average.The spatial distribution pattern of PM_2.5concentration in Chinese cities in 2020showed a trend of high in the east and low in the west,and high in the north and low in the south.The Yangtze River and the Hu Huanyong Line are the boundaries between the high and low PM_2.5concentration areas in China.The north of the Yangtze River radiates outward through two high pollution centers in Xinjiang Province and the North China Plain.The PM_2.5concentration values show a downward gradient trend,and the air quality has improved.Most areas south of the Yangtze River have good air quality.From the dispersion degree of PM_2.5concentration distribution,the coefficient of variation in the northern region is much higher than that in the southern region.The concentration of PM_2.5in various cities in China shows a significant spatial positive correlation,with significant spatial agglomeration.The hot spots show a spatial distribution pattern of more in the north and less in the south,and more in the east and less in the west.The hot spots mainly gather in the Beijing Tianjin Hebei urban agglomeration,the Bohai Rim urban agglomeration,and the urban agglomeration near the Central Plains of the Yangtze River;Cold spots are mainly concentrated in the Yungui Sichuan region and the Pearl River Delta urban agglomeration in the southeastern coastal areas.However,the correlation between PM_2.5concentrations in the Northeast and Northwest regions of China is not significant.Among the influencing factors of PM_2.5concentration in Chinese cities,socio-economic factors have a greater impact on PM_2.5concentration than meteorological factors.From the results of the Geographically Weighted Regression Model（GWR）,it can be seen that among meteorological factors,each meteorological factor has a negative correlation effect on the PM_2.5concentration in the vast majority of Chinese cities,with precipitation and temperature having the strongest impact on the PM_2.5concentration in Chinese cities.Among socio-economic factors,the proportion of the secondary industry and the number of taxis have a positive correlation effect on the PM_2.5concentration in various cities in China;The per capita GDP,population,industrial nitrogen oxide emissions,and coal consumption are mainly positively correlated with the PM_2.5concentration in Chinese cities,while the overall social electricity consumption,green coverage in built-up areas,and total liquefied gas supply are mainly negatively correlated with the PM_2.5concentration.Among them,coal consumption,population,taxi ownership,and green coverage of built-up areas have the greatest impact on the PM_2.5concentration in Chinese cities.