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.为响应排放管控策略，泰国皇家政府下属污染控制部（Pollution Control Department, PCD）需对道路机动车车队的排放量开展估算。机动车排放量的估算值，通过将特定类别机动车的行驶里程（vehicle kilometer traveled, VKT）估算值与相应的排放因子（emission factor, EF）相乘得到。排放因子被定义为特定类别机动车针对特定污染物的平均估算排放速率。排放因子的计算依据包括平均车速、环境温度、昼夜温差、海拔高度、燃料挥发性以及检查/维护（I/M）项目；上述输入参数的变动会改变最终生成的排放因子数值。研究团队针对不同类别的机动车，在泰国汽车排放实验室（Automotive Emission Laboratory, AEL）内开展了排放测试，并在多种工况下测量了一氧化碳（CO）、碳氢化合物（HC）、氮氧化物（NOx）、颗粒物（PM）以及空气有毒污染物（Air Toxics）的排放水平，测试工况涵盖燃料类型及其品质、发动机技术、行驶车速与行驶模式等场景。后续将基于本次实测排放结果，合理推导并计算泰国各类机动车的排放因子。本次研究共针对四类机动车开发了四类核心机动车排放因子，分别为摩托车（motorcycle, MC）、轻型汽油车（light duty gasoline vehicle, LG）、轻型柴油车（light duty diesel vehicle, LD）以及重型柴油车（heavy duty diesel vehicle, HD）。上述排放因子将被用于估算研究区域内的移动源排放负荷，该负荷将结合年度交通调查数据进行测算。本次研究成果将为泰国后续制定合理的空气污染管控政策与措施提供支撑，尤其可为移动源污染管控相关工作提供决策依据。