Study On The Influence Of COVID-19 Epidemic On Air Quality In Anhui Province

In the Spring Festival of 2020,novel coronavirus pneumonia(Corona Virus Disease 2019,COVID-19)was widespread throughout the country.In order to fight COVID-19,the whole country is united and has taken a series of strict anti-epidemic measures,such as traffic control,home isolation,delay to work and seal the country and the city,which has curbed the rapid spread of the epidemic in a short time.The epidemic not only brings serious damage to the economy,but also has an important impact on air quality.Although the academia has carried out many useful explorations on the environmental impact of the epidemic,most of the domestic researches focus on the national level,urban agglomerations,Hubei Province,Shandong Province and individual cities,and there are few literatures on Anhui Province.As one of the important provinces in the central region rising,Anhui Province has a rapid economic growth in recent years,but the air pollution problem is prominent.It is of great practical significance and decision-making value to study the impact of the epidemic on air quality in Anhui Province,which is helpful to identify the relationship between air pollution and human economic activities in this region,and has important enlightenment for Anhui Province to improve air quality scientifically.This paper mainly includes four aspects of progressive research work:first,based on the monthly air quality data of 16 prefecture level cities in Anhui Province from December 2014 to December 2020,taking the area of each prefecture level city as the weight,the provincial air quality of Anhui Province is calculated.Based on the provincial data,using statistical charts,this paper explores the evolution law of air quality in Anhui Province from 2015 to 2020,and analyzes the air quality situation in Anhui Province in 2020.Secondly,aimed at the provincial air quality index(AQI)and six major air pollutants(PM2.5,PM10,SO2,CO,NO2,O3)respectively,using Python statsmodels package,according to the Akaike information criterion(AIC)and the mean absolute percentage error(MAPE),the optimal parameter combination mode is selected from 1024 parameter combinations(p,d,q)×(P,D,Q)s,and combined with the significance of parameter estimation and whether the model conforms to the basic statistical assumptions,the SARIMA prediction model is established to estimate the expected value of air quality in Anhui Province in 2020 under no epidemic situation.Thirdly,by comparing the actual and expected values of air quality,according to the concentration difference of air pollutants(i.e.the actual value minus the expected value)and the percentage of the difference,the dynamic impact effect of the epidemic on air quality was studied,and the difference of the average impact effect of the epidemic on different pollutants was analyzed.In addition,the difference of the impact effects of the epidemic on different pollutants were analyzed in severe periods of air pollution or epidemic.Finally,based on the above research results,combined with the correlation of pollutants,epidemic prevention and control dynamics and meteorological status,as well as the representative pollutants of pollution sources,the mechanism of the epidemic on air quality of Anhui Province was preliminarily analyzed.Through the study,the main findings are as follows:(1)the SO2 pollution treatment effect is significant in Anhui Province,but the NO2 and O3 pollution need to be paid attention to.Compared with 2019,the annual average AQI of Anhui Province decreases by 2.85%and the annual average concentration of SO2 decreases by 18.74%in 2020 under no epidemic situation.On the contrary,the annual average concentrations of both NO2 and O3 increase by more than 12%.(2)The epidemic helps to improve the air quality of Anhui Province in general,especially to reduce NO2 pollution,but it aggravates SO2 pollution.Compared with no epidemic,the epidemic renders that the annual average AQI of Anhui Province decreased by 9.42%,and the average concentration of NO2 decreases by 19.24%in 2020,on the contrary,the annual average concentration of SO2 increases by 7.88%.(3)The impact of the epidemic on AQI,PM10,SO2,CO and NO2 in Anhui Province shows an approximate "W"shape distribution,the impact on PM2.5 shows an approximate "V" shape distribution,and the impact on O3 shows an approximate bell shape distribution.For AQI,PM10,CO and PM2.5,the impact of the epidemic in February was the largest;For NO2,the impact of the epidemic in January was the largest.Except for NO2,five other pollutants and AQI rebounds in December,indicating that Anhui Province will face severe air pollution control pressure in the post epidemic era.(4)The epidemic will change the coupling relationship of different air pollutants.Under the background of the epidemic,the direction of correlation between secondary pollutants O3 and primary pollutants NO2 and CO remains unchanged,but the intensity becomes weak:O3 and NO2 change from strong negative correlation to moderate negative correlation,O3 and CO change from extremely strong negative correlation to strong negative correlation.This study identified the evolution law of air quality in Anhui Province,clarified the dynamic impact effect of the epidemic on air quality in Anhui Province,explored the effect of economic blockade on the reduction of different air pollutants under the background of the epidemic,and revealed the mechanism of the epidemic on air quality in Anhui Province.The research results have a certain reference value for the decision-making departments in the region to formulate environmental policies scientifically.