Unexpected Impact of COVID-19 Lockdown on the Air Quality in the Metro Atlanta, USA Using Ground-based and Satellite Observations

Abstract

We studied the impact of COVID-19 (coronavirus disease 2019) lockdown on the air quality over the Atlanta area using satellite and ground-based observations, meteorological reanalysis data and traffic information. Unlike other cities, we found the air quality has improved slightly over the Atlanta area during the 2020 COVID-19 lockdown period (March 14 -April 30, 2020), compared to the analogous period of 2019 (March 14-April 30, 2019). Ground NO 2 concentrations have decreased slightly 10.8% and 8.2% over the near-road (NR) and urban ambient (UA) stations, respectively. Tropospheric NO2 columns have reduced 13%-49% over the Atlanta area from spaceborne observations of TROPOspheric Monitoring Instrument (TROPOMI). Ground ozone and PM2.5 have decreased 15.7% an ~5%, respectively. This slight air quality improvement is primarily caused by the reduced human activities, as COVID-19 lockdowns have reduced ~50% human activities, measured by traffic volume.. Higher wind speed and precipitations also make the meteorological conditions favorable to this slight air quality improvement. We have not found a significant improvement in Atlanta amid the lockdown when human activities have reduced ~50%. Further studies are needed to understand the impacts of reduced human activities on atmospheric

Ozone and Particulate Matter Variations in Southwest Ohio, USA, during the COVID-19 Pandemic in 2020

“…The decreasing trend is consistent with two other studies (Bekbulat et al, 2021;Chen et al, 2020). The average ozone concentration at the Taft site was 32 ppb during Similarly, Atlanta, GA, which is also NOx-limited, ozone decreased during the lockdown when NOx emissions decreased (Huang et al 2021). In contrast, Chicago, IL was in a transitional regime (in between VOC and NOx-limited) during the summer of 2020, which resulted in increased ozone concentrations.…”

“…Comparing with the same time in 2019, NO2 reductions during the lockdown period (March 14-April 30, 2020) were 10.8% and 8.2% respectively at these two sites, with 15.7% ground level ozone reductions and 5% PM2.5 reductions (Huang et al, 2021). These reductions were attributed to a 50% reduction in traffic.…”

“…These drastic changes in people's lives also affected the surrounding environment such as air and water quality. There have been multiple studies and reports around the world on air pollution comparisons during the lockdown period with previous years, and reported significant decreases of criteria air pollutants, such as PM2.5 and NO2, from both ground and satellite monitoring (Huang et al, 2021;Ogen, 2020;Torkmahalleh et al, 2021).…”

Assessment of COVID-19 Impacts on Air Quality in Ulaanbaatar, Mongolia, Based on Terrestrial and Sentinel-5P TROPOMI Data

“…Studies have proved these tropospheric NO2 hotspots in downtown and midtown areas are associated with human activities including ground traffic and industrial activities (Hashim et al, 2021;Huang et al, 2021;Rissman et al, 2013). Apparently, just after lockdown measurements Previous studies have also shown a reduction of tropospheric NO2 columns in 2020 lockdown period over various regions in the world (Goldberg et al, 2020;Hashim et al, 2021;Huang et al, 2021;Wang et al, 2021). Likewise, similar results have been reported in Asia regions, particularly…”

“…Remote sensing-based approaches have contributed to air quality assessments at various scales ranging from local studies -often in affected cities -(e.g., Huang et al, 2021;Prunet et al, 2020) to regional and national-level investigations (e.g., Shikwambana et al, 2020;Stratoulias and Nuthammachot, 2020;Zheng et al, 2019) and global studies (e.g., Lim et al, 2020). Particularly, studies focusing on NO2 to thoroughly understand the effects of the COVID-19 lockdown on the…”