Ponente
Descripción
The COVID-19 outbreak has caused significant reductions in traffic and economic activities, impacting anthropogenic emissions and urban air quality. The covid perturbation on the emissions are estimated by comparing publicly available energy and economic datasets between 2019 and 2020. The perturbation impacts are then evaluated by comparing the Weather Research and Forecasting with Chemistry (WRF-Chem) model simulations with aircraft measurements from University of Maryland and Scientific Aviation, and with the satellite retrievals from the TROPOspheric Monitoring Instrument (TROPOMI) and Aura Ozone Monitoring Instrument (OMI). Compared to the aircraft measurements over New York City, Houston, and Denver, the emission perturbation has much larger impacts on concentrations of nitrogen dioxide (NO2) than CO, despite larger reductions in the CO anthropogenic emissions, suggesting the significant impacts through secondary formation from biogenic sources. Also, the impacts on NO2 and CO concentrations are larger over New York City than Houston and Denver, suggesting the heterogenous responses from large cities across the US during the COVID-19 pandemic. Compared to satellite retrievals, our model is able to capture the observed changes in tropospheric NO2 columns over urban source regions between 2019 and 2020, demonstrating the reasonable estimates of the COVID perturbation on the anthropogenic emissions. In addition, we find the emission perturbation dominates the observed reductions in tropospheric NO2 over urban source regions, with meteorological impacts tending to increase tropospheric NO2 by 2-8%.
