Research On Air Quality Evaluation And Prediction In Lvliang

With the acceleration of the national urbanization process,the air pollution of China is relatively serious.In recent years,the government has introduced many policies for air pollution control.In 2013,the Action Plan for Air Pollution Prevention and Control was proposed,which means that air pollution prevention and control has been officially put on the agenda.Shanxi Province is a province with abundant resources,and many cities have severe air pollution.Their air quality rankings are relatively low in the country.Lvliang City is one of the prefecture level cities in Shanxi Province,and the ranking is relatively low in the country.Therefore,air pollution control work needs to be further strengthened.In order to make the air quality of Lvliang City better,this article analyzes the spatiotemporal trend of air pollution from 2015 to 2022 and uses the fuzzy comprehensive evaluation method to evaluate the air quality.In order to determine the main pollution problems and sources of pollutants in Lvliang City,the grey correlation method is used to analyze the correlation degree of various influencing factors on the air quality in Lvliang City.Then,empirical mode decomposition（EMD）is combined with short-term neural network method（LSTM）to establish an EMD-LSTM prediction model to predict the pollutant concentration in Lvliang City from 2023 to 2025,and finally the article propose relevant countermeasures and suggestions based on the research results.The main content and achievements are as follows:（1）When studying the spatiotemporal changes in air quality in Lvliang City,the article mainly show interannual and intra year changes by analyzing the proportion of excellent days,AQI change trends and pollutant concentration changes.It could be found that the proportion of excellent days in Lvliang City was the lowest in 2017,AQI was the highest,and pollutant concentration was also the highest.In 2022,the proportion of excellent days was the highest,AQI was the lowest,and PM_2.5was reduced to below25μg/m³,PM₁₀was about 70μg/m³.In space,using Arcgis software to analyze the trend of comprehensive quality index and main pollutants in various regions from 2019 to2022,it can be found that the comprehensive quality index was the highest in 2019 and the lowest in 2022.Jiaocheng County,Wenshui County,Fenyang City,and Xiaoyi City had higher comprehensive quality index and heavier air pollution,while Fangshan County,Lishi District,Shilou County,and Jiaokou County had lower comprehensive quality index and lighter air pollution;In 2019,the concentration of pollutants was the highest,and in 2022,the concentration was the lowest.Jiaocheng County,Wenshui County,Fenyang City,and Xiaoyi City had higher concentrations of PM_2.5,SO₂,and ozone,while Liulin County,Zhongyang County,and Xiaoyi City had higher concentrations of PM₁₀,NO₂,and CO.（2）This article selects the fuzzy comprehensive evaluation method as the evaluation method and calculates the comprehensive weight of each pollutant concentration through entropy weight method and exceedance multiple method,and then it calculates the membership matrix based on the reduced trapezoidal function.Finally it calculates the comprehensive evaluation vector S andμValue and air quality level.It could be found that the air quality was the worst in 2019 and the best in 2022 from 2019to 2022.The overall concentration of pollutants in Jiaokou County and Shilou County was relatively low,while the concentration of pollutants in Wenshui County and Jiaocheng County was relatively high.The main sources of pollutants included natural sources such as blowing sand and floating dust and anthropogenic sources such as nitrogen oxides from motor vehicle exhaust emissions,industrial production exhaust gas and cooking oil fume pollution.（3）The article selects 19 indicators about socio-economic factors and meteorological factors,and calculates the correlation degree between these indicators through the grey correlation analysis method.It can be found that the factors that affect the concentration of pollutants are urban green area,regional gross domestic product,industrial raw coal quantity,and social electricity consumption,and the least affected is energy conservation and environmental protection expenditure.（4）The EMD-LSTM model is selected as the prediction model to predict the concentrations of six pollutants from 2023 to 2025.Through the EMD-LSTM model,the nonlinear changes of the actual value and the predicted value curve of PM_2.5,PM₁₀and O₃are consistent,but the actual value and the predicted value curve of SO_2,CO and NO₂concentrations have a large deviation.And through testing error,we could know root mean square error（RMSE）of PM_2.5,PM₁₀,O₃,SO₂,CO and NO₂are0.2,0.06,0.08,0.18,0.52,0.22.（5）In response to the main problems and influencing factors in air pollution in Lvliang City,the article writes some countermeasures and suggestions from the perspectives of the government,enterprises,and residents.The government should deepen the law enforcement work of atmospheric environmental protection,implement environmental protection supervision,promote the integration of government and enterprises,enhance carbon sequestration strength,optimize social electricity consumption structure and control mobile source emissions;Enterprises should control exhaust emissions,standardize dust management and increase the control of oil fume pollution;Residents should establish the concept of green development and cultivate the habit of green living.