Short-term effect of COVID-19 lockdowns on atmospheric CO2, CH4 and PM2.5 concentrations in urban environment

Abstract

The COVID-19 pandemic has changed all areas of human activity as it forced the authorities around the world to enact unprecedented restrictions such as "lockdowns". The low economic activity reduced the anthropogenic impact on the environment, in particular, greenhouse gases and aerosols emissions were decreased. However, the associated change in air quality is difficult to directly observe and quantify, since concentrations of these components in urban areas are affected by many other factors. In this work statistical analysis of atmospheric CO 2 , CH 4 and PM 2.5 , measured in 2017-2020 in the city of Ekaterinburg, Russia, are presented. A detailed focus was made on the lockdown period from March 28 to April 30, 2020. A significant decrease in concentrations and inter-hourly variations of all studied components were observed only in the short "self-isolation" period from April 6 to April 8. The anthropogenic origin of this effect, primarily associated with the reduction in vehicular traffic, was concluded from mean diurnal cycles and air temperature correlations of all components. A decrease in the difference between measured and background CO 2 and CH 4 mole fractions was also found during this period. The difference was 1.3±0.2 ppm for CO 2 and 8±4 ppb for CH 4 , which was many times lower than during any other observed periods, suggesting a short-term effect of lockdown restrictions. Overall, a negative impact on the atmosphere quickly resumed after the recovery of economic activity. The approaches in this study can be used to detect weak fluctuations of atmospheric components in other urban territories.

Temporal variations of CO2 and CH4 concentrations in the surface atmospheric layer according to measurements in the Middle Urals

“…Continuous monitoring of atmospheric CO2, CH4 mole fractions has been carried out an urban monitoring site at the Institute of Industrial Ecology of the Ural Branch of Russian Academy of Sciences (IIE UB RAS), Yekaterinburg (56.85° N; 60.65° E) since 2015 [4]. From September 2021, measurements were organized at a background station.…”