Breakpoint Regression Analysis Of Air Pollutants During The Epidemic

Air,as the "life gas" we breathe every day,its quality is related to our health and living standard.With the sustainable development of the economy,the ecological environment has become worrisome.Since 2013,our country has paid more and more attention to environmental protection work,and has issued a lot of relevant policies to control pollution.After years of efforts,the effects of these policies are obvious.There are more and more blue sky and white clouds,and the number of days for air quality to meet the standard is also increasing.However,due to the high basic emissions in our country,even when a variety of social activities are suspended,the Beijing-Tianjin-Hebei region still experienced heavy smog.In addition,the concentration of PM2.5 in China from January to March was still more than three times higher than the safe level proposed by the World Health Organization.Therefore,improving our country’s air quality is not only a tough battle,but also a protracted battle.It is also very valuable to explore and analyze the influencing factors of air pollution and make feasibility suggestions.This paper explores the impact of COVID-19 on air quality and explores the reasons for changes in air quality changes through heterogeneity analysis.Firstly,the Regression Discontinuity is introduced,and the basic concept of the model and the method of model checking are clarified.Then,the variables are introduced,and the causes and harms of six kinds of air pollutants are introduced to facilitate the analysis of the results.In the empirical research part,considering the impact of meteorological factors on air quality,the research time is January and February 2020.And these two months are divided into two phases,namely,the period of strict control of the epidemic and the orderly resumption period,so as to explore the impact of strict epidemic control and resumption of work on air quality.We make regression analysis on the air quality index and six kinds of air pollutants in these two periods,and test the validity and robustness of the model results.The empirical results show that during the period of strict control,the air quali-ty index drops at the break point,which indicating that the air quality is significantly improved.The analysis of six kinds of air pollutants show that the concentrations of PM2.5,PM10,NO2,SO2 and CO all decrease,but the concentration of O3 increase.Preliminary analysis show that the decrease of the concentration of five pollutants is mainly related to traffic and industry,while the increase of O3 concentration is related to meteorological conditions.The empirical results during the resumption of work and production show that the air quality coefficient and the concentration of six pollutants have increased to varying degrees,which indicates that air quality begins to deteriorate as people continue to carry out production and life.Finally,the heterogeneity analysis is carried out to explore the in-depth causes of air quality changes through urban heterogeneity.Through the heterogeneity regression,it is found that the shutdown of transportation and manufacturing industry is the main reason for the improvement of air quality during the period of strict control of the epidemic.To sum up,the changes in air quality and air pollutant concentration are caused by the combined effects of internal and external factors.The internal cause is the emission of air pollutants caused by human activities,and the external cause is the change in meteorological conditions.As the weather conditions are not controlled by human activities,the improvement of air quality still depends on human activities.According to the analysis of the empirical results,the improvement of air quality can be achieved through both transportation and industry.Encouraging public trans-portation,the development of new energy vehicles,and the innovative development of clean energy in industry can help us win the protracted battle to defend the blue sky.