The Analysis And Evaluation Of The Temporal And Spatial Risk Characteristics Of PM2.5 Pollution

Over the past half century,China has made remarkable achievements in industrialization,urbanization and modermization,but the ensuing air pollution should be worrying.PM2.5,though relatively low in the atmosphere,has the greatest impact on air quality,atmospheric visibility and public health.Meanwhile,short-term or long-term exposure to PM2.5 will cause a series of acute and chronic health risks.And these health risks will impose a heavy economic burden.This study aims to fill in the gaps in the spatial-temporal analysis of PM2.5 pollution in Chinese cities from 2015 to 2018,as well as the spatial-temporal assessment of health risks and economic risks caused by PM2.5 pollution from 2015 to 2017.This research results provide policymakers with the latest PM2.5 pollution prevention and control information in the new environmental situation,help to define pollution prevention and control priority areas,and coordinate regional economic development model to deal with the increasingly serious air pollution prevention and control problems.Based on the latest PM2.5 concentration and socio-economic data of 367 cities in China,the characteristics of PM2.5 pollution in China from 2015 to 2018 were analyzed from the perspective of spatial and temporal trends,and the seasonal,monthly and daily spatial and temporal patterns of PM2.5 pollution in the year of 2018 were analyzed as an example.In addition,spatial autocorrelation analysis was used to analyze the spatial concentration of PM2.5 in different time scales.The spatial and temporal risk characteristics of PM2.5 pollution in China from 2015 to 2017 were assessed from the perspective of health risk and economic risk respectively,and the uncertainty of the risk assessment model was assessed by Monte Carlo simulation method.In this study,the characteristics of PM2.5 pollution in China under the new situation of environmental protection were analyzed,and the spatiotemporal risk assessment was carried out from the perspective of health risk and economic exposure caused by pollution.At the same time,the degree of difficulty in pollution control was classified according to natural and socio-economic factors.The results are as follows:(1)From the perspective of spatiotemporal distribution,the regional characteristics of PM2.5 pollution distribution are closely related to the distribution characteristics of topography and landform,and the overall PM2.5 pollution level in China from 2015 to 2018 is on the decline.The average annual concentration decreased year by year,and the urban compliance rate increased.The seasonal average concentration was "the best in summer,the same in spring and autumn,and the worst in winter".The monthly average concentration presents a U-shaped distribution trend,and the PM2.5 concentration in winter is about twice as high as that in summer.The average daily concentration showed pulse fluctuation,the amplitude was larger in winter and smaller in summer.In the past four years,Chengdu-Chongqing City Groups,Yangtze river delta urban agglomerations,Liaozhongnan City Groups,and Harbin-Changchun megalopolis have achieved significant improvement.The high concentration area is mainly distributed in the central and eastern part of China and the southern part of Sinkiang.The central and eastern part of Sinkiang shrinks northward and westwards with the north China plain as the core.The southern part of Sinkiang shrinks and shifts from the western Tarim basin to the Turpan basin,and the year of 2016 is the inflection point of this area.(2)From the perspective of spatial aggregation,hot spots are mainly concentrated in the north China plain,Jianghan plain,the eastern loess plateau and the southern part of Sinkiang.In the middle and eastern parts,hot spots are expanding to the Fenwei plain,the Jiangsu-Anhui coastal plain and the Dongting lake plain.The cold spots are mainly concentrated in the northern greater Hinggan mountains,the Hengduan mountains and the western the Taiwan strait.The cold spots in the southwest gradually extend to the Yunnan-Guizhou plateau and the eastern part of the Qinghai-Tibet plateau,and the cold spots in the northeast extend to the eastern Inner Mongolia plateau.(3)From the perspective of spatiotemporal risks,the overall health risk and economic exposure caused by PM2.5 in China showed a decreasing trend from 2015 to 2017.However,there were still a large number of people affected by the annual health problems,and the total annual economic losses still accounted for a relatively high proportion of the total annual GDP.High-risk areas are mainly distributed in the eastern central and southwestern region in Sinkiang,including the Beijing-Tianj in-Hebei urban agglomeration,Central Plains urban agglomeration,Shandong peninsula urban agglomerations,Jinzhong City Group,Guanzhong plain city group,west of Wuhan urban agglomeration,the Yangtze river delta urban agglomeration,Changsha-Zhuzhou-Xiangtan City Group,Chengdu-Chongqing urban agglomeration and urban agglomeration,as well as the Sinkiang Kashgar and Hetian region,and low risk areas are widely distributed in the northwest(except southwest Sinkiang),southwest(with the exception of Chengdu-Chongqing City Group),northeast(except the Harbin-Changchun megalopolis)and south China,etc.(4)From the point of view of the degree of difficulty in governance,natural factors lead to the most difficult governance in Western Tarim Basin and Turpan Basin,while social and economic factors lead to the more difficult governance of Beijing-Tianjin-Hebei urban agglomeration,Central Plains urban agglomeration,Jinzhong City Group,western Shandong Peninsula urban agglomeration,Guanzhong plain city group,Wuhan metropolitan area and Changsha-Zhuzhou-Xiangtan City Group.In contrast,Chengdu-Chongqing City Group,Harbin-Changchun megalopolis,Liaozhongnan City Group,and the Poyang Lake City Group difficult to manage.