Impact Assessment of COVID-19 on Variations of SO2, NO2, CO and AOD over East China

The COVID-19 (Coronavirus Disease 2019) broke out in the late of 2019. On January 23 in Wuhan, and later in all other cities of the country, there were taken measures to control the spread of the virus through quarantine measures. This article focused on East China and attempted to assess comprehensively the environmental impact of the COVID-19 outbreak. This study analyzed satellite observational data of sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and aerosol optical depth (AOD) in the period before the outbreak of the epidemic and during the implementation of preventive measures and control of COVID-19, as well as compared it with the data obtained in the same period of 2019. The results of the analysis showed that the COVID-19 lockdown improved air quality in the short term, but as soon as coal consumption at power plants and refineries returned to normal levels due to the resumption of their work, pollution levels returned to their previous level. The levels of CO and NO2 showed the most significant decrease (20 and 30%), since they were mainly associated with a decrease in economic growth and transport restrictions that led to a change in energy consumption and a reduction in emissions. This study can complement the scientific community and environmental protection policy makers, not only to assess the impact of outbreak on air quality, but also for its effectiveness as a simple alternative program of action to improve air quality.