Study On Qilian Mountain National Park Expressway Area Atmospheric Carrying Capacity Of Traffic Volume

Qilian Mountain National Park is one of the important ecological function areas in China.With the development of economy in China,the opening and future development of scenic spots in Qilian Mountain National Park,the number of motor vehicles on the expressway in this area will continue to increase,the atmospheric environment of expressway area is affected to a certain extent,and motor vehicles have become the expressway area main pollution source of air pollution.Based on the ecological protection of Qilian Mountain National Park,this paper determines the boundary of expressway,analyzes the influencing factors of atmospheric environment capacity of expressway and combines with the meteorological data of expressway,calculates the atmospheric environment area capacity of expressway area.COPERT model is used to analyze the emission factors of motor vehicles on expressways,the emission factors are calculated according to the parameters required by the model,and the calculation model of atmospheric carrying traffic volume on expressway area established and analyzed.The main research contents are as follows:（1）To explore the ecological composition and characteristics of the expressway area of Qilian Mountain National Park,by analyzing the diffusion mechanism of vehicle exhaust on expressway and combining with the line source diffusion model of air pollutants,the boundary expressway was determined as 300 meters with the diffusion distance of air pollutants as the limit.（2）According to the characteristics of motor vehicle exhaust emissions and air pollutants,CO,SO₂,NO₂ and PM were selected as the main influencing factors of the expressway area atmosphere.Analyze the regional meteorological conditions of the expressway area,reasonably determine the parameters of the model based on the improved A-value method,obtain the atmospheric environmental capacity of pollutants in the expressway area,analyze the main influencing factors according to the monthly change of atmospheric environmental capacity of pollutants.（3）COPERT model is applied to analyze the emission factors of motor vehicles driving on the expressway,combined with the atmospheric environmental capacity of the expressway area,and the calculation model of the atmospheric carrying traffic capacity of expressway area is established;According to the classification of motor vehicle types in China’s expressway and COPERT model,the classification standards of vehicle types are unified,and the variation of emission factors of each type of motor vehicles on the expressway at different speeds is calculated by using COPERT model.（4）The calculation of the atmospheric environment carrying capacity of CO,SO₂,NO₂and PM shows that the atmospheric traffic carrying capacity of CO,NO₂and PM is much greater than the existing traffic volume of the study section,indicating that the traffic volume of expressway is not limited by the three atmospheric influencing factors.The carrying capacity of SO₂atmospheric environment is slightly larger than the existing traffic volume of the study section,in order to ensure the safety of the atmospheric environment of the expressway area,the recommended driving speed of motor vehicles is proposed according to the maximum carrying traffic volume of each atmospheric influencing factor,with SO₂ as the main factor and other influencing factors as the auxiliary factor.