EVALUATION OF EMISSION FACTORS FOR LIGHT - DUTY VEHICLES IN TAIWAN

摘要

Motor vehicles are a major source of urban air pollution. Accurate motor vehicle emission estimates are essential to the understanding and controlling of air pollution. This study aimed to estimate the fleet-average emission factors of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) for gasoline-fueled, light-duty vehicles of year 1997 model in Taiwan. Light-duty vehicles have three categories: passenger cars, taxi cars, and light-duty trucks. Measurements from a roadway tunnel study and from dynamometer testing reported in the literature were considered in this study to induce "suggested" fleet-average emission factors of passenger cars. These "suggested" emission factors were recommended to estimate vehicle emission inventory in Taiwan. Then, the suggested emission factors of passenger cars were combined with those factors derived from the remote sensing data to produce another set of suggested fleet-average emission factors of taxi cars and light-duty trucks. Finally, all these suggested emission factors were used to calibrate the U.S. MOBILE 5b emission factor model with typical Taiwan-specific vehicle data. The results showed that the suggested emission factors for light-duty vehicles were 17-30 g/km for CO, 4-7 g/km for HC, and 1.3-2.3 g/km for NOx at a vehicle speed of 30 km/h. The calibration factors for the MOBILE 5b model as applied in Taiwan were 0.6-0.9 for CO, 1.3-2.5 for HC and 0.8-1.6 for NOx.