Spatiotemporal Changes in Global Nitrogen Dioxide Emission Due to COVID-19 Mitigation Policies

Abstract This paper investigates spatiotemporal changes of nitrogen dioxide (NO2) tropospheric vertical column density due to the COVID-19 pandemic using satellite observations before, during and after the lockdown (hereafter referred as the pre-, peri- and post-periods) in six different countries: China, South Africa, Brazil, India, the UK and the US, and compare these periods with 2019 as well as mean climatology from 2010-2019. We observe significant declines in relative differences (RDs) from the pre- to peri-period (as compared with the 10-year climatology) in most study countries including China, South Africa, India, and the UK by 15, 17, 8 and 7% respectively. The US does not demonstrate significant decline with RD difference relatively small at just 2%. Meanwhile, although the 2020 RD of Brazil is 7% lower than 2010-2019, this trend is quite similar to that of 2019 (20% vs 23%). In the post-period of 2020, the NO2 columns rebound in most target countries: China, US, South Africa, Brazil and UK, with similar RDs relative to the corresponding pre-period as compared with 2019 and 2010-2019. In contrast, NO in India continues to be influenced by the ongoing COVID-19 crisis with pre-to-post RD 8% lower than the average of previous ten years.