| Abstract | Traffic emissions contribute a substantial amount of air pollutants and climate forcers but have not been investigated properly especially in Asian developing cities. This emission inventory study was conducted to the emission from vehicle fleet (buses, trucks, taxis, personal cars and motorcycles) in Ho Chi Minh City (HCMC) in 2013 using International Vehicle Emission (IVE) model. Questionnaire surveys, GPS monitoring and video camera were conducted. The average age of buses, trucks, taxis, personal cars and motorcycles was 6.4, 11.7, 6, 7.6 and 12.6 years, respectively. Except for personal car fleet which has more advanced technologies, i.e. 6% complied with Euro III or Euro IV, other types of surveyed vehicles were still at most of Euro II. The average vehicle kilometer traveled for each types of vehicles was calculated using regression equation of odometer reading and age of vehicles obtained from the questionnaire surveys. The emission factors produced by IVE model under actual driving patterns and local-specific meteorological conditions in the city were used to estimate emission for base case of 2013. Emission factors of HCMC were higher than that of the other cities for PM and NOx, especially for bus and truck fleet. The total annual emissions of major pollutants of CO, VOC, NOx, PM, CO₂ in Tg (teragrams)were 3.1, 0.4, 0.5, 0.05 and 53.6 Tg, respectively. Two “what if” faster technology implementation scenarios were set in term of changing technology and changing fuel types: scenario 1 assumed that all the entire vehicle fleet in 2013 met at least Euro III, while scenario 2 assumed the entire vehicle fleet would use cleaner fuel, except for MCs. The emission of air toxic pollutants under scenario 1 and 2 would be reduce by 66.6% and 2.2%, respectively and the 20 year-horizon GWP would be simultaneously decreased by 49.9% and 34.6%, respectively. The faster technology intrusion would bring about significant co-benefits for both air quality and climate forcing mitigation. |