Evaluation Of Ambient Air Quality In Hefei And Analysis Of Its Influencing Factors

With 11 state-controlled stations for automatic air quality monitoring in Hefei from 2018 to 2020,this paper follows sulfur dioxide（SO₂）,nitrogen dioxide（NO₂）and fine particulate matter(PM_2.5)。Based on the monthly average and annual average concentrations of inhalable particulate matter(PM₁₀),carbon monoxide（CO）and Ozone（O₃）,the temporal and spatial variation characteristics of main pollutants at 11stations in Hefei from 2018 to 2020 are analyzed.At the same time,the air environmental quality of 11 stations in Hefei is evaluated by fuzzy comprehensive method,and the influencing factors of ambient air quality in Hefei are analyzed.The main conclusions are as follows:（1）By analyzing the monitoring data of Hefei in 2020,it is concluded that the air quality of Hefei in 2020 is dominated by PM_2.5pollution,and the comprehensive pollution index has an upward trend.Among them,SO₂,NO₂,PM_2.5,PM₁₀and CO are high in winter and low in summer;O₃is low in winter and high in summer.（2）The distribution characteristic of NO₂mass concentration is that the concentration at the junction of Baohe district station,Luyang district station and Yaohai district station is the highest,and then diffuses around.Then the concentration value at Dongpu reservoir station and Yaohai district higher education base station decreased significantly.The concentration of SO₂gradually decreases from west to East.Its distribution feature is that it diffuses westward from the higher education base station in Yaohai district,forming a high concentration area crossed by Luyang district station,Shushan district station and Baohe district station,and diffuses around.The spatial distribution of O₃mass concentration is characterized by a gradual decline from the middle Shushan station to the surrounding area.The spatial distribution of PM₁₀concentration is higher in the north than in the south,and higher in the east than in the West.PM_2.5decreases gradually to the southwest at the intersection of Yaohai district station and Baohe district station,and the concentration in the south is the lowest.（3）The fuzzy comprehensive method is used to analyze and evaluate the air quality of 11 stations in Hefei from 2018 to 2020.The stations with better air quality include higher education base,high tech zone and Baohe district,and the stations with poor air quality include Yaohai district,Sanli street and Luyang district.From 2018 to2020,the air quality of only five stations,including higher education base,high tech zone,Baohe district,Binhu New Area and Dongpu reservoir,is getting better and better.（4）The fuzzy comprehensive method is used to analyze and evaluate the air quality of 11 stations in Hefei from 2018 to 2020.The stations with better air quality include higher education base,high tech zone and Baohe district,and the stations with poor air quality include Yaohai district,Sanli street and Luyang district.From 2018 to2020,the air quality of only five stations,including higher education base,high tech zone,Baohe district,Binhu New Area and Dongpu reservoir,is getting better and better.The air quality assessment shows that the primary pollutant in Hefei is PM_2.5.The correlation analysis of PM_2.5shows that the linear correlation between PM_2.5and PM₁₀is the best,followed by NO₂,CO and SO₂,and there is no obvious linear relationship between PM_2.5and O₃.PM_2.5is a component of PM₁₀,so it has a high correlation.There is an obvious correlation between PM_2.5and NO₂.（5）The air quality assessment shows that the primary pollutant in Hefei is PM_2.5.The correlation analysis of PM_2.5shows that the linear correlation between PM_2.5and inhalable particulate matter(PM₁₀)is the best,followed by NO₂,CO and SO₂,and there is no obvious linear relationship between PM_2.5and O₃.PM_2.5is a component of PM₁₀,so it has a high correlation.There is an obvious correlation between PM_2.5and NO₂.Through the grey correlation degree method and Pearson correlation analysis method,the factors affecting the ambient air quality in Hefei are studied,and the quantitative analysis is carried out from two aspects:natural factors and economic factors.The results show that natural factors:sunshine hours have the greatest impact on NO₂,SO₂,CO and PM_2.5,and the greatest impact on O₃is the average temperature.PM_2.5is most affected by rainfall.Economic factors:according to the close relationship with SO₂concentration,it is sorted into exhaust gas pollutant emission,total population,greening coverage,total vehicle ownership,per capita GDP and GDP.According to the close relationship with NO₂concentration,it is sorted into greening coverage,total population,exhaust pollutant emission,per capita GDP,GDP and total vehicle ownership.For PM_2.5that the closeness of concentration relationship is sorted as follows:exhaust pollutant emission,greening coverage,total population,per capita GDP,GDP and total vehicle ownership.