| In recent years,with the rapid increase of the number of motor vehicles in xi ’an,the impact of vehicle exhaust emission pollutants on the air quality in xi ’an has become increasingly prominent,which seriously threatens the physical and mental health of citizens.Therefore,it is of practical significance to study the characteristics of vehicle emission pollutants in xi’an city.This article is based on 2011-2015 xi ’an motor vehicle ownership,vehicles,fuel type and basic data,such as the traffic speed,respectively in xi ’an a main road to hydrocarbons(HC),carbon monoxide(CO)and nitrogen oxides(NOx),and other major pollutants monitoring;Calculation and analysis of nearly five years of motor vehicle emissions as well as the main pollution factor,the share rate of using MOVES model to predict the xi ’an motor vehicle exhaust pollution total vehicle exhaust emissions and the different stage.It reveals the characteristics and law of pollutant emission of motor vehicles in the last five years in xi ’an.The results show that:(1)2011-2015,xi ’an and private motor vehicles locomotive’s rapid growth,the average annual growth rate of 13.95%and 13.95%respectively,xi ’an motor vehicle has reached 2.3745 million cars and 2015 of private car ownership accounted for 83.15%;Xi’an motor vehicle emissions in 2011-2015 a linear growth trend,the average annual growth rate of 11.56%;2011-2015,xi ’an motor vehicle emissions are on the rise,CO,HC and NOX of average annual growth rate of 12.47%,12.76%and 11.41%respectively,among them,the fastest growing CO emissions,it accounts for more than 80%of the discharge of major pollutants emissions from all sources.(2)according to the share rate of vehicle pollutants,passenger car’s HC and CO emissions share the largest proportion of total vehicle emissions,more than 47 percent annually,followed by motorcycles.Gasoline car is carbon monoxide(CO)and hydrocarbons(HC)emissions are the main share models,the share rate was over 90%,and diesel emissions of nitrogen oxides(NOx)accounted for 55.38%of the auto emissions;Countries before and the emission standard car,its emissions of pollutants accounted for 54.59%of the auto emissions;Ⅲ and over discharge standard of automobile and countries,its emissions of pollutants accounted for 45.41%of automobile emissions.(3)the road monitoring test was conducted by using horizontal distribution monitoring method for two roads in the north street of xi’an and the Eurasian road.The highest concentration of PM2.5,CO and NO2 in the north street of xi’an is 253,g/m3,87.2 PPM and 1.7 PPM respectively.The highest concentrations of PM2.5,CO and N02 in chanba avenue are 109 mu g/m3,53.8 PPM and 1.4 PPM respectively.The attenuation rate of north street at 0-50 m is 6.9%,17.61%and 25%respectively,respectively.The attenuation rate is 9.09%,24.89%and 41.67%respectively.The monitoring data shows that the pollutant concentration on both sides of the urban road is higher.Pollutants attenuation change law is consistent,but the attenuation of city suburbs than in the city road,the road on the outskirts of the reason for this is that open spread easily,decay faster on gas emissions of pollutants,and city commercial circle,the road is narrow,and around buildings,pollutants with the increase of the road distance is not easy to spread.(4)According to the《Technical guidelines for the compilation of emission inventories for road vehicles and vehicles(trial)》,Measured in different stages of the xi’an vehicle exhaust emissions,found that the Ⅱ vehicle emissions of various pollutants emissions before about 60%of total emissions,and the proportion of ownership is only 20%～30%.It can be seen that the emission standard of motor vehicles should be increased,the yellow standard cars and old vehicles with low emission standard should be eliminated,and the emission supervision of vehicles should be strengthened. |
PDF Full Text Request