Evaluation Of The Diffusion Characteristics And Exposure Levels Of Mobile Source Pollutants On The Capital Ring Expressway And Analysis Of Emission Reduction Scenarios

In recent years,China’s economic level has developed rapidly.With the continuous increase in travel demand,the traffic volume on highways has shown an increasing trend.The exhaust emissions of motor vehicles on highways have gradually become an important source of air pollution,and the emission reduction of highways has become a key link in regional traffic management.The Capital Ring Expressway passes through areas such as Langfang,Baoding,Zhangjiakou,and Chengde,surrounding Beijing.It has the characteristics of long total mileage,high traffic volume,and high emissions.Therefore,the exhaust emissions from motor vehicles on the Capital Ring Expressway pose a serious burden on the air quality of the areas along the route.In order to overcome the difficulties of highway emission reduction and promote regional traffic governance and sustainable development,this study uses the MOVES model,CALPUFF model,and pollutant exposure function to analyze and extract the diffusion characteristics and exposure levels of motor vehicle pollutant emissions on the Capital Ring Expressway.Based on this,scenario analysis is used to explore the pollutant reduction effects under different emission reduction scenarios.Finally,reasonable suggestions are proposed for highway motor vehicle emission reduction.Firstly,combined with the localized MOVES model,the 2019 list of motor vehicle pollutant emissions from the Capital Ring Expressway was calculated.The results show that the daily average emissions of motor vehicle pollutants on the G95 highway in 2019 were 53.41 tons.Among them,CO and NOX emissions account for the largest proportion,followed by HC,and PM10 and PM2.5 account for the smallest proportion of total emissions.From a regional perspective,the order of pollutant emissions from large to small is Baoding,Zhangjiakou,Tangshan,and Chengde;From the perspective of vehicle models,the small passenger cars and large trucks have the highest pollutant sharing rate among the six vehicle models.Secondly,based on the pollutant data obtained from the MOVES model,the CALPUFF air quality model was used to simulate the pollutant diffusion process of the Capital Ring Expressway in July 2019.The results show that the concentration of motor vehicle pollutants on the Capital Ring Expressway is in descending order:CO>NOx>CH4>PM10>PM2.5.The pollutants diffuse along the expressway to both sides,and the farther away from the expressway,the lower the concentration of pollutants.Due to terrain limitations,there are differences in the diffusion concentration of pollutants on both sides of the highway.From the perspective of spatial distribution,the overall concentration of pollutants in the capital ring road area shows a distribution characteristic of higher in the south than in the north and higher in the east than in the west.To further explore the impact of motor vehicle pollutants on the health of residents in surrounding areas on highways,an exposure dose model was introduced to evaluate the degree of impact of pollutants on different populations.Calculate the exposure level of pollutants based on the diffusion concentration obtained from the CALPUFF model.The calculation results indicate that the degree of impact of pollutants on the population is related to their concentration,and the order of pollutant exposure levels from high to low is CO>NOx>CH4>PM10>PM2.5.Meanwhile,among the three categories of population,young and middle-aged people are the most affected by pollutants,followed by the elderly and primary and secondary school students.This trend is related to the activity levels of different age groups.Finally,predict the traffic volume of the Capital Ring Expressway in 2025 and establish a scenario analysis model.Set up five scenarios to quantitatively compare the emission reduction effects of different scenarios.The results show that the pollutant reduction effect is most significant under the comprehensive scenario.Finally,based on the scenario analysis results and combined with the actual situation along the route,reasonable suggestions for emission reduction work in the capital ring road area are proposed from the government,enterprises,and the public levels.This study takes the emission of pollutants from motor vehicles on highways as the starting point,comprehensively considers its diffusion characteristics and the degree of impact on different populations,and provides theoretical basis and emission reduction suggestions for the prevention and control of motor vehicle pollution on highways,in order to promote the green development of highways.