Fractional Order Gray Prediction Of Air Quality In The Middle Reaches Of Yangtze River Urban Agglomeration Under Net Zero Target

With the accelerated industrialization and urbanization in China,the region represented by the middle Yangtze River urban agglomeration is facing a serious air pollution problem while the economy is developing at a high speed.In the context of the " Net Zero" goal,China has put forward more stringent requirements for air pollution prevention and control,helping to accelerate China’s air pollution control and the realization of the " Net Zero" goal.Therefore,re-measuring the future trend of air quality is urgent to effectively alleviate the serious ecological problems of air pollution and guide the treatment of air pollution.To this end,this thesis takes Wuhan,Changsha and Nanchang,the representative cities of the middle reaches of the Yangtze River urban agglomeration,as the study area,and carries out a study with air quality as the research theme.(ⅰ)Using correlation analysis to establish the correlation among the connecting levels of air quality influencing factors,so as to construct the transmission mechanism of air quality influencing factors to air quality.The factors influencing air quality are discussed in terms of meteorological conditions,pollution sources and socio-economic aspects.Correlation analysis was used to study the correlation between influencing factors and air quality.The main influencing factors of air quality and the modeling factors of each pollutant were also screened.(ⅱ)Considering the linear and nonlinear characteristics of the time series of air quality impact factors,the fractional-order inverse cumulative operator with new information priority and reduced model solution perturbability is introduced.The fractional-order inverse cumulative univariate models,namely N＿SAIGM＿FRAO model and GM＿FRAO(1,1)model,are constructed.In addition,air quality is affected by multiple factors,so a fractional order inverse cumulative multivariate gray model(FGOM(1,N))is constructed.The parameters of the new model are subsequently optimized by a cultural algorithm.The N＿SAIGM＿FRAO model and GM＿FRAO(1,1)model can better describe the linear and nonlinear characteristics of the time series.the FGOM(1,N)model can measure the effects of different factors on air quality.Their prediction accuracies all belong to the high precision interval and have good prediction ability.(ⅲ)Considering the policy effects of the "Net Zero" goal on air quality and comparing air quality in different treatment contexts.The N＿SAIGM＿FRAO model and GM＿FRAO(1,1)model were used to predict the main air quality factors for scenarios 1 and 2,respectively.In Scenario 3,the prediction of the main air quality impact factors is set according to the policies corresponding to the " Net Zero" target.Finally,based on the scenario prediction results of air quality influencing factors and FGOM(1,N)model to predict the air quality of three cities in 2022-2030.And the development of air pollutants in different cities under different scenarios are analyzed and compared.The results of the study show that 1)The comprehensive energy consumption of ten thousand yuan of output value and total coal consumption in Wuhan,Changsha and Nanchang will decrease gradually under three scenarios in the future period,and the overall trend will gradually become stable.The number of civil cars and the greening rate of built-up areas showed a steady increase.2)Wuhan’s industrial emissions decreases gradually under the three scenarios in the future period.In contrast,industrial emissions in Changsha and Nanchang still tend to increase in the future.3)Wuhan,Changsha,and Nanchang have the lowest concentrations and fastest rates of decline in the net-zero emission scenario,while all meet the primary standards.The concentrations and decrease rates in the established policy setting scenario are lower than those in the baseline scenario.(4)Under the three scenarios of baseline,established policy settings,and net-zero emissions,it is clear that Wuhan has better air quality than Changsha and Nanchang,while Changsha is slightly inferior.To this end,the following recommendations are made: 1)Reducing fossil fuel consumption and increasing the use of " Net Zero" energy.2)Increasing the promotion of new energy vehicles,and effectively raising the proportion of new energy in large transport vehicles.3)Promoting the optimization and upgrading of industrial structure,breaking through the technological needs of pollution reduction,and achieving industrial " Net Zero".4)Strengthening the government to deepen the publicity of "net zero" and improve the supervision and assessment mechanism of "net zero" emissions.