An Empirical Study On The Impact Of Industrial Emissions In Qingshuitang District On Air Quality In Zhuzhou City

Zhuzhou City is a typical industrial city.It is located in Qingshuitang old industrial zone of Zhuzhou City.There are more than200 industrial enterprises with high emissions such as smelting,chemical industry,building materials and thermal power.It is one of the largest sources of pollution in Zhuzhou City.The national policy of ecological civilization construction and industrial transformation and development lists Qingshuitang old industrial zone as one of the 21 old industrial zone reconstruction pilots in the country.This research uses the excellent case of the closure of enterprises in the Qingshuitang old industrial zone and the sudden drop of industrial emission sources,combined with the regression discontinuity design method and the PMF source analysis method,to research the effect of the industrial emissions in the Qingshuitang old industrial zone on the air quality of Zhuzhou City,to make a scientific assessment of the impact of the closure of enterprises in the Qingshuitang old industrial zone on the air quality of Zhuzhou City,and to provide a reference for government departments to make environmental governance and environmental management decisions.First,this paper researches the time series characteristics of AQI and six major pollutants in Zhuzhou City,and finds that all indicators except O₃ showed a step-like decline in 2015.Especially,the decreasing trend of SO₂ concentration of trace pollutants in Qingshuitang area is consistent with the time point when the enterprises in Qingshuitang old industrial zone were shut down,it can be qualitatively inferred that the measures of shutting down are effective in improving the air quality of Zhuzhou City.Secondly,regression discontinuity design model was established to reserch the effect of industrial emissions in the Qingshuitang old industrial zone on the air quality of Zhuzhou City.The results of the regression discontinuity estimation were passed the robustness test and the placebo test,which both confirmed the validity of the benchmark regression results.It is concluded that the reduction of industrial emission sources in Qingshuitang old industrial zone has an improvement effect on the air quality of Zhuzhou City.Finally,by analyzing the pollution characteristics of the chemical components of the primary pollutant PM_2.5in Zhuzhou City,and using the PMF model to analyze the source of PM_2.5,and combined with the source emission inventory to correct the PMF source analysis results,get the share rate of PM_2.5 industrial emission sources,which is mutually confirmed with the quantified air quality improvement effect,and the more scientific main conclusions of this researches are obtained.The main conclusions of this thesis are:（1）The regression discontinuity design method was used to explore the effect of industrial emissions on the air quality of Zhuzhou City in Qingshuitang old industrial zone,the results show that the reduction of industrial emission sources in Qingshuitang old industrial zone has an improvement effect on the air quality of Zhuzhou City.Among them,the monthly and daily average values of AQI decreased by 27.5%and 18.9%respectively before and after the breakpoint,and the monthly average mass concentrations of PM_2.5,PM₁₀,NO₂,SO₂ and CO decreased by about39.0%,35.5%,9.3%,17.5%and 5.7%respectively before and after the relocation.The daily average value decreased by about 45.5%,25.7%,15.8%,9.9%and 7.7%before and after the relocation,respectively.（2）The source analysis results of PM_2.5 from October 7,2021 to February 26,2022,combined with the source emission inventory correction,obtained the sharing rate of industrial emission sources is 26.1%.Compared with2013 and 2016,the share rate of industrial emission sources in Zhuzhou City decreased by 15.9%and 14.0%respectively,indicating that the reduction of industrial emission sources has an improvement effect on the air quality of Zhuzhou City,which can be used to support the empirical conclusions of the regression discontinuity design.（3）PM_2.5 is an important indicator to measure the air quality of Zhuzhou City.From2013 to 2021,the annual average concentration of PM_2.5 in Zhuzhou City exceeded the national ambient air quality secondary concentration limit,and from March 11,2021 to February 26,2022,the daily average concentration of PM_2.5 in Zhuzhou City was 35.26±23.93μg/m³,which exceeded the national ambient air quality level 1 concentration limit.The pollution of PM_2.5 is still not optimistic,and it is necessary to strengthen the pollution control of PM_2.5.