A new database of on-road vehicle emission factors for Colombia: A case study of Bogotá

Mobile sources contribute directly or indirectly with most of the atmospheric emissions in Colombian cities. Quantification of mobile source emissions rely on emission factors (EF) and vehicle activity. However, EF for vehicles in the country have not evolved at the same time as fleet renovation and fuel composition changes in the last few years. In fact, estimated EF before 2010 may not reflect the reduction of sulfur content in diesel and the renovation and deterioration of passenger vehicles; therefore, emission levels may be over or under estimated. To account for these changes, we have implemented the MOVES model in Bogota and obtained a new database of on-road vehicle emission factors. For this purpose, local information of activity rates, speed profiles, vehicle population distribution and age, meteorology and fuel composition was used. Emissions were estimated with these new set of EF and compared with previous inventories. We observed large reductions in SO2 (-87%), CO (-65%) and VOC (-62%) emissions from mobiles sources and lower reductions in NOx (-20%). Other pollutants such as PM2.5 (+15%) and CO2 (+28%) reported increases. This paper includes a new database of on-road vehicle emission factors for Bogota, which can be applied in other Colombian cities in the absence of local data.