A Study Of The Effects Of The Deterioration Of Vehicle On Pollutant Emission Factors Based On Chassis Dynamometer Tests

In recent years, the number of motor vehicles in China has increased rapidly, causing haze, acid rain, visibility deterioration and many other environmental problems. Studies have shown that 60% of the pollutants resulted from 20% of vehicles that had the highest accumulated mileages. Therefore, the study of the impacts of pollutant emission factors by vehicle deterioration can accurately distinguish the high-emission vehicles. This can provide a theoretical basis for the governments to reduce air pollutant emissions from the vehicles.In the present study, the gasoline passenger vehicles and light-duty trucks were divided into 36 and 24 classes by the four categories in which the vehicles were built (Grade Ⅰ, Grade Ⅱ, Grade Ⅲ, and Grade Ⅳ). This study selected carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) as target pollutants. Based on the chassis dynamometer testing method, the pollutant concentrations from different types of gasoline vehicles were measured and converted into emission factors based on the mileages. The relationship between the pollutant emission factors for different categories of the vehicles and accumulated mileage was analyzed and established. Further, we compared this study to the basic emission factors in the IVE model and previous study. The basic emission factors in the IVE model were modified by this work. Finally, total gasoline passenger vehicles and light-duty trucks emissions of China in 2010 were calculated on the basis of the deterioration model.The results show that the emission factors varied with vehicle types. It was found that three pollutant emission factors increased exponentially with the accumulated mileages. The pollutant emission factors for the gasoline passenger vehicles with the accumulated mileage of 200,000 kilometers were about two times of the new car. When the accumulated mileage reached 250,000 kilometers, pollutant emission factors increased by another 50%. The deterioration of vehicles had a significant impact on pollutant emission factors. It was found that the CO and HC emission factors established in this study were generally lower than basic emission factors in the IVE model, while the NOx emission factors were generally higher than the IVE model. We simulated the pollutants concentrations by OSPM model, which was found that the NO2 simulation results with the modified emission factors are more close to the observations relative to the basic emission factors in the IVE mdel. The correction to the IVE Model was reasonable. The gasoline passenger vehicles and light-duty trucks in China emitted CO (HC and NOx) of 6.3 and 1.3 (0.4 and 0.1,1.0 and 0.2) million tons in 2010, respectively.