Study On The Characteristics Of Air Pollution In Beijing,tianjin,hebei And Surrounding Areas And The Transmission Of Pollutants In Typical Cities

In recent years,with the acceleration of urbanization and industrialization,urban air pollution is becoming more and more serious.For this reason,our government has promulgated a series of policies and made great progress in the prevention and control of air pollution throughout the country.However,"2+26"cities in Beijing-Tianjin-Hebei and surrounding areas as transmission channel cities of air pollution,the transmission of air pollutants between cities has a great impact on regional air quality,and the air pollution problem is still prominent because of its dense industrial industry and large population.Therefore,it is of great significance to explore the air pollution situation in this region for regional joint prevention and control.This study is based on atmospheric pollutant concentration data(PM_2.5,PM₁₀,NO₂,SO₂,O₃,CO)and meteorological data in Beijing-Tianjin-Hebei and its surrounding areas from 2015 to 2019.This paper comprehensively analyzed the air quality changes of"2+26"cities in recent years and the influence characteristics of meteorological elements on pollutants in typical provincial capitals（Beijing,Zhengzhou,Jinan and Taiyuan）,and further combined the backward trajectory model（HYSPLIT）,potential source analysis（PSCF）and concentration weight analysis（CWT）.The transport paths and potential source distribution characteristics of major atmospheric pollutants(PM_2.5,PM₁₀ and O₃)in typical cities are discussed.The following conclusions were obtained:（1）During the study period,the air quality of"2+26"cities was improved to a certain extent,and PM_2.5,PM₁₀ and O₃ often appeared as the primary pollutants in each city.The concentrations of PM_2.5,PM₁₀,SO₂,NO₂ and CO decreased year by year,and the seasonal characteristics were the highest in winter and the lowest in summer.The monthly and daily changes were U-shaped characteristics.The O₃ concentration increased year by year,the seasonal characteristics were the highest in summer and the lowest in winter,and the monthly and daily changes were the inverse U-shaped characteristics.Correlation analysis shows that the concentrations of SO₂,NO₂ and O₃are highly correlated among different provinces and cities,and particulate matter PM_2.5and PM₁₀ in the whole region are significantly positively correlated with NO₂ and CO.（2）Meteorological conditions have different degrees of influence on pollutant concentration in different cities.Temperature has the least influence on the concentration of pollutants in Beijing.Humidity has the greatest influence on the concentrations of CO and SO₂ in Beijing and Zhengzhou,on the concentrations of SO₂and O₃ in Jinan,and on the concentrations of SO₂ and PM₁₀ in Taiyuan.The effect of wind speed on pollutant concentration in each city is ranked as NO₂>CO>PM_2.5,SO₂>O₃,PM₁₀.The concentration of O₃ in Taiyuan is most affected by atmospheric pressure,showing a significant negative correlation.Other pollutants in Zhengzhou,except O₃,are significantly affected by atmospheric pressure,showing a positive correlation.（3）The four typical cities are mainly affected by the short-distance air flow in the surrounding areas and the long-distance air flow in the northwest direction.In Beijing,PM_2.5 and O₃ are mainly affected by short-distance air flow in Jinan,Hengshui and Baoding,while PM₁₀ is mainly affected by long-distance air flow in southwest Russia and Bayannur League.PM_2.5,PM₁₀ and O₃ in Zhengzhou are mainly affected by short-distance air flow in Suizhou and Rizhao.In Jinan,PM_2.5 and PM₁₀ are mainly affected by the short-distance air flow in the west,east and northwest direction.O₃ is mainly affected by the short-distance air flow from the Yellow Sea area.PM_2.5 and O₃ in Taiyuan are mainly affected by the short-distance air flow in Kaifeng,and the long-distance air flow from Xilin Gol League also has a great influence on PM_2.5 and PM₁₀.（4）The analysis of potential sources shows that the potential sources of PM_2.5 in Beijing are mainly distributed in Datong,Linfen,Baoding,Zhangjiakou,Anyang and Xinxiang,but the seasonal distribution is not obvious.In Zhengzhou,Jinan and Taiyuan,PM_2.5 pollution sources mainly come from most parts of the province,with the most extensive impacts in winter and the least impacts in summer.In addition,the border areas of each province have contributed to the PM_2.5 pollution in the four cities.Anyang,Xinxiang,Shangqiu,Jiyuan,Jiaozuo,Puyang,Heze,Jinan,Liaocheng,Shijiazhuang and Jinzhong are the four typical provincial capitals’key public areas for PM_2.5pollution prevention and control.