| The rapid development of my country’s Socioeconomic level and urbanization process,which has increased the demand for motor vehicle among the people,which directly leads to the aggravation of motor vehicle exhaust pollution.In this case,the research for the characteristics of vehicle pollutant emissions and the establishment of emission inventories have played an effective guiding role,while also providing targeted control measures and policies for government departments.In recent years,Guiyang City’s ozone level has exceeded the standard,which may be related to the photochemical phenomenon of pollutants emitted by motor vehicle exhaust.It has been paid attention to by the local government department.Therefore,Guiyang is selected as a case city in this paper.the following conclusions were obtained:On account of research on the emission characteristics of volatile organic compounds(VOCs)from motor vehicles in Guiyang,the tunnel experiment is used to analyze,two different tunnels were selected to analyze the emission characteristics of motor vehicles VOCs,A total of 79 VOCs emission factors were obtained,and it was obtained that propane and butane were the components with higher pollution concentrations at the entrance and exit of the two tunnels.The total emission factors of motor vehicles in urban tunnels and high-speed tunnels in Guiyang were 27.45±8.1mg/km and 35.82±10.8 mg/km,respectively,as the characteristic product of evaporative emission from gasoline vehicles,Isopentane is the highest emission factor component in the two tunnels.The emission factors in urban tunnels and high-speed tunnels are 2.52±1.04 mg/km and 2.09±1.28 mg/km,respectively.In general,establish an emission inventory of traditional motor vehicles that based on the total number of motor vehicles in 2018 and the motor vehicle emission factors provided by "Technical Guidelines for the Compilation of Road Motor Vehicle Air Pollutant Emissions Inventory" in Guiyang.The results shows that the total emissions of VOCs,CO,NOx and particulate matter(PM)were 8.95 kt and 46.42 kt,32.08 kt and 2.19 kt,respectively.From a multi-angle analysis of the contribution rate of emissions:(1)Model: micro,small passenger cars contribute the most to VOCs and CO,heavy trucks were the main source of contribution to NOx and PM.(2)Fuel type:gasoline-fueled vehicles were the main contribution source of VOCs and CO,diesel-fueled vehicles were the main contribution source of NOx and PM.(3)Emission standards: the contribution rates of VOCs,CO,NOx and particulate matter of motor vehicles under the three and four national standards are 55.32%,55.20%,87.70% and 91.57%,respectively.Finally,based on the survey information of the actual road network and road traffic in Guiyang,a spatial and temporal distribution map of Guiyang’s gradual increase in 2018 was established.and the VOCs emissions of Guiyang City were preliminarily estimated based on the tunnel experiment.It is obtained that the heavily polluted areas in Guiyang were mainly concentrated in Yunyan District,Nanming District and Guanshan Lake District,and the polluted areas show that significant linear characteristics.Analysis of the discharge characteristics of different seasons shows that the pollution in winter polluted areas was more polluted than other seasons,and the heavily polluted areas were more obvious.comparing the working days and the non-working days,it found that the regional characteristics did not change significantly.According to the analysis of time changes,the alternate emission reached the lowest value at 4:00 in the morning,and the highest emissions periods were mainly affected by travel regulations at 8:00 and 17:00 in the afternoon.Daily emission analysis showed that emissions were reduced.The emission working days were slightly larger than the non-working days.expressways were the roads with the highest emissions among the four road types.the annual emission analysis results show that Huaxi District is the area with the most volatile pollutant emissions.The emissions of VOC,CO,NOx and PM were 3.17 kt,13.22 kt,5.17 kt and 0.27 kt in Huaxi District,respectively.Substitute hydrocarbon was the largest amount of VOCs emission from motor vehicles in urban roads and expressways,which were 3.16 kt and 1.89 kt,respectively. |
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