Changing Spatial Distribution of NO2 in Atlanta During the COVID-19 Pandemic

Abstract:

Atmospheric composition in urban areas was significantly altered as people began to stay home during the COVID-19 pandemic. High-resolution NO₂ retrievals from TROPOMI provide new capability of tracking intra-urban variability of air pollution, thereby differentiating the effect of the pandemic on emissions in different neighborhoods. We focus our analysis on Atlanta, GA, which is typically a top-ranked US city for traffic congestion, and is also home to the world’s busiest airport. We use a large set of NO_x observations, including TROPOMI NO2 retrievals, in-situ measurements from EPA monitoring sites, and additional in-situ and Pandora measurements near the airport, to assess the change in spatial patterns of air pollution during the onset of the pandemic and as the city went through various stages of reopening. We show that the combined in-situ and satellite observational network captures the temporally different changes in emissions from on-road traffic and aviation. Specifically, on-road traffic dipped to its lowest point in early April and quickly recovered in late May. In contrast, air traffic dropped to its lowest in May, and currently remains low. Measurements are ongoing at the time of abstract submission, and we will continue to track the evolving pandemic response. We assess the ability of TROPOMI to quantify differential impacts of COVID on these source sectors, and discuss the use of this measurement set to constrain emissions inventories.