Spatial and temporal characterization of vehicular emissions in Ecuador using VEIN

Resumen

Air pollutants concentrations reach high levels in developing countries. However, due to the lack of measurements, too often, this problem remains unseen. In Ecuador, top-down inventories classify on-road vehicles as the main source of air pollution, as well in cities in Ecuador. In order to unveil the importance of these sources of air pollution, we developed a detailed vehicular emission for Ecuador at the province and monthly level. We used the model VEIN, which is an R+Fortran package, to estimate emissions, which can generate inputs for air quality models [1]. The activity data was retrieved from national statistics, which includes a comprehensive characterization of the circulating fleet by type of vehicle, fuel, and service. For instance, 90% of the fleet consumes gasoline, 8.5% diesel, and the rest are hybrid vehicles, GLP and electric. Also, 36% are simple passenger vehicles, 20% sport utility vehicles (SUV), 34% motorcycles, 1.5% buses and 8.5% trucks. The emission factors come from the Environmental European Agency [2] corrected for Ecuador conditions, considering deterioration and the chemical composition of fuels. Our estimations covered 12 pollutants and estimates of hot-running, cold-start, evaporative, and wear. For 2019, the total emissions in Ecuador were 109097 (t/y) for CO and 13666 (t/y) NMHC. In addition, 4-stroke motorcycles between 50 and 250 cc emitted 30% of CO and 24% of NMHC. Our results are consistent with local estimates, although global inventories overpredict emissions for Ecuador.