Updated mobile source emission factors in Thailand

In response to emission control strategies, the Royal Thai government by the Pollution Control Department (PCD) is obligated to estimate emissions from on-road vehicle fleets. Estimates of vehicle emissions are obtained by multiplying an estimate of the vehicle kilometer traveled (VKT) by a given class of vehicles by an appropriate emission factor (EF). The EF is defined as the estimated average emission rate for a given pollutant for a given class of vehicles. EFs are based on average speeds, ambient temperature, diurnal temperature range, altitude, fuel volatility and I/M programs; changes in these input assumptions alter the resulting emission factors. The different class of motor vehicles were conducted emission tests in the Automotive Emission Laboratory (AEL),Thailand and pollutants such as CO, HC, NOx, PM and Air Toxics were measured under different situations such as fuel type and its quality, engine technology and driving speed and patterns for example. The emission results will be developed appropriately to calculate as emission factors of each vehicle types in Thailand. There are 4 mainly motor vehicle emission factors developed for 4 class of motor vehicles which are motorcycle (MC),light duty gasoline vehicle (LG),light duty diesel vehicle (LD) and heavy duty diesel vehicle (HD). Those emission factors will be applied to estimate mobile source emission loading in study areas which will be investigated with traffic data yearly. The outcomes will be supported in further appropriated policy and measure to manage and control air pollution problem in Thailand particularly mobile sources.