Abrupt declines in tropospheric nitrogen dioxide over China after the outbreak of COVID-19

TL;DR

This study uses satellite data to show a significant 48% decline in tropospheric nitrogen dioxide over China following COVID-19 lockdowns, highlighting the environmental impact of reduced economic activities during the pandemic.

Contribution

It quantifies the impact of COVID-19 policy interventions on nitrogen dioxide levels and links these reductions to specific government actions in China.

Findings

48% reduction in nitrogen dioxide levels post-lockdown

Reductions associated with government announcements and lockdown dates

Environmental impact of decreased fossil fuel consumption during COVID-19

Abstract

China's policy interventions to reduce the spread of the coronavirus disease 2019 have environmental and economic impacts. Tropospheric nitrogen dioxide indicates economic activities, as nitrogen dioxide is primarily emitted from fossil fuel consumption. Satellite measurements show a 48% drop in tropospheric nitrogen dioxide vertical column densities from the 20 days averaged before the 2020 Lunar New Year to the 20 days averaged after. This is 20% larger than that from recent years. We relate to this reduction to two of the government's actions: the announcement of the first report in each province and the date of a province's lockdown. Both actions are associated with nearly the same magnitude of reductions. Our analysis offers insights into the unintended environmental and economic consequences through reduced economic activities.