Study On Vehicle Emission Factor In Xi'an City

As a transport of modern society,the vehicles bring a great convenience to people's life,meanwhile, cause unavoidable environmental problems,Vehicle exhaust pollution has become a worldwide public hazard. According to statistics,in the global world, CO and NOx emissions are 3.5 million tons and 9.3 million tons respectively, with 59% of CO,43% of NOx from transportation.In our country,the national motor vehivle quantities is 169.935 million, and discharges 5143.3 tons emissions, in 2009. Vehicle becomes the main contributor in pollutants. The dirty air threat the human's environment and health greatly.The MOBILE6.2 mobile source emission factor model developed by USEPA is applied in calculating vehicle composite emission factor of Xi'an, Scenario analysis is used in testing input parameters's sensitivity that affects 5 emissions factors VOC, NOx, CO, PM and CO2. Sensitivity analysis shows that:different parameter has different affection. And there are only 2 sensitive parameters for CO2,5 sensitive parameters for PM,9 sensitive parameters for NOx,13 sensitive parameters for VOC and 13 sensitive parameters for CO.According to the local vehicle characteristic of Xi'an, got the localization of simplified input model with collecting the relevant data and revising the model. Model the vehicle composite emission factor in 1996. The compare between road runnel testing and the simulant outputs show:the values of YOC, CO from the road tunnel testing and the model output are similarity. The value of NOx from the model are almost a factor of 2 times of the testing datas.Finally, using the simplified model of localization model the vehicle emission factor in 2011-2020 of XI'an. According the output values, learn that motor vehicle emission factors in Xi'an has a large degree of reduction. And compared to 2011, HC emission factors decreases 41.9%, CO emission factors decreases 20.2%, NOx emission factors decreases 52.3%, PM emission factors decreases 22.2%.There is no model to caculate the emission factor from the vehicle source in China, so using the USEPA developed MOBILE6 2 model is a good way to caculate the vehicle composite emmision factor.