Validation of the 2021 Emission Inventory for Cuenca, Ecuador, Through Weather and Air Quality Modeling in the Framework of WRF-Chem

The last atmospheric emission inventory for Cuenca, a city located in the Andean region of southern Ecuador, was developed for the year 2021 (EI 2021) and encompasses both primary pollutants (NO_x, CO, VOC, SO₂, PM₁₀, and PM_2.5) and greenhouse gases (CO₂, CH₄, and N₂O). We formally assessed the quality of this emission inventory by modeling air quality levels in October 2021 using the Weather Research and Forecasting with Chemistry (WRF-Chem 3.2) model at a high spatial resolution (1 km). Although we conducted simulations with different combinations of boundary conditions for chemical species and hourly profiles to disaggregate daily on-road traffic emissions, we selected two sets of numerical experiments to report. The results indicated that most of the assessed meteorological and air quality variables were modeled acceptably, suggesting that the EI 2021 emission inventory is a reasonable estimation of real emissions. The results also indicated the current capacity of WRF-Chem to model the atmosphere in a complex Andean city using the “one atmosphere” approach, highlighting the variables with good, fair, and poor modeling performance. We propose future research directions to improve emission inventories and the performance of atmospheric modeling in the Equatorial Andean region. Finally, the results and spatial distribution of the EI 2021 were compared to the emission data from the last version of the EDGAR Emissions Dataset (which has a spatial resolution of 11.1 km), one of the most used global emission datasets. We concluded that, for the Equatorial Andean region and for modeling purposes, the EDGAR Dataset results should be reviewed, both to account for the effects of height above sea level on the magnitude of primary pollutant emissions and their spatial configuration.