Research On The Atmospheric Environmental Carrying Capacity Based On System Dynamics

Gaoxian County of Yibin City is one of the key areas of air pollution prevention and control in Sichuan Province,and its air pollution is compound pollution mainly composed of PM_2.5.Air pollution not only harms human physical and mental health but restricts the development of the social economy.The key areas of air pollution prevention and control should adjust the industrial structure and energy structure,and strive to form a development pattern matching with the atmospheric environmental carrying capacity.Therefore,it is urgent to evaluate and predict the atmospheric environmental carrying capacity of Gaoxian County in order to coordinate the contradiction between economic development and atmospheric environmental protection.Taking Gaoxian County of Yibin City as the research object,combined with the current situation of meteorological,socio-economic,and atmospheric environmental quality in the research area,a System Dynamics?SD?model of the"population-economy-energy-atmospheric environment"in Gaoxian County was established by using SD.The authenticity of the model was verified by the historical data of the past ten years.Three scenario development modes set up to use the SD model to simulate the changing trend of population,economy,energy,and air pollutant emissions under different development modes.Comprehensively evaluate the time point when the average annual concentration of PM_2.5 drops to 35?g/m³ under the three modes,and screen out the best developing mode.Under the environment-friendly development mode,the carrying capacity index method was used to predict and evaluate the carrying capacity of the atmospheric environment in Gaoxian County of Yibin City.The main research results are as follows:?1?System dynamics?SD?is a useful tool to study atmospheric environmental carrying capacity.The SD model of the"population-economy-energy-atmospheric environment"is reasonable and reliable.The model ignores the physical and chemical processes of simulating the transport and diffusion of atmospheric pollutants and establishes the dynamic relationship among population,economy,energy,and the atmospheric environment by introducing the proportional coefficient and conversion rate of pollutants,which shows that SD is a powerful tool for studying complex systems.The authenticity of the SD model of atmospheric environmental carrying capacity in Gaoxian County of Yibin City was tested by using the historical data of household registration population,GDP,comprehensive energy consumption,and PM₁₀ emissions from 2010 to 2018.The results of the comparative analysis show that the errors between the simulated values and the real values of each variable are within 10%,and the model construction is accurate and reasonable.?2?Prediction and evaluation of atmospheric environmental carrying capacity in Gaoxian county.The three development models were evaluated from the perspectives of economy,energy,and atmospheric environment.During the prediction period,only the average annual concentration of PM_2.5 of the environmental protection development model can reach the secondary standard.In 2028,the average annual concentration of PM_2.5 in Gaoxian county will fall to within 35?g/m³.The evaluation results of the atmospheric environmental carrying capacity index show that NO₂ has the best atmospheric environmental carrying capacity.After 2020,the atmospheric environmental carrying capacity index of NO₂ is-0.69,which will reach the highest level and be in a state of high carrying capacity.The atmospheric environmental bearing capacity of SO₂ is good,and it is in the medium bearing range for a long time in the prediction period.In 2035,its atmospheric environmental carrying capacity index will be-0.71,and it will be in a state of high carrying capacity.The atmospheric environmental carrying capacity of PM₁₀ is poor.During the forecast period,the atmospheric environmental carrying capacity index of PM₁₀ is-0.07?-0.08,all of which are in a critical overload state.The atmospheric environmental bearing capacity of PM_2.5 is still severe.Before 2025,in Gaoxian,the atmospheric environmental bearing capacity of PM_2.5 will be in an overload state and change into a critical overload state after 2028.?3?The PM_2.5 and PM₁₀ in Gaoxian County are still in critical overload conditions.To improve the carrying capacity of the atmospheric environment,efforts need to be made in terms of industrial structure,energy consumption structure,and air pollution control.The local government should intensify the adjustment of regional industrial layout,resolutely implement national industry regulations,strictly control industry access,and raise the entry barrier for industries that do not meet air quality standards.Optimize the energy consumption structure,accelerate the development of clean energy,and rationally exploit and utilize clean energy such as shale gas,solar energy,water conservancy and hydropower,and biofuels.