Impact of Wave COVID-19 Responses on Black Carbon Air Pollution in Moscow Megacity Background

Globally the impact of COVID-19 lockdown on environmental pollution is evidenced. How significant it was due to social and working restrictions during different pandemic waves is still uncertain. Aerosol black carbon (BC) in the Moscow megacity background is measured during first wave COVID-19 lockdown and recovery periods in spring and summer of 2020, and at the same times in 2021 when pre-lockdown and lockdown of the third pandemic wave occurred. Economic and population activities in conjunction with meteorological parameters and air mass transportation are evaluated by studying the variability and concentration levels of black carbon. Because the strict social and working restrictions in lockdown 2020 the mean BC concentration dropped down to 1.5 +/- 0.9 mu g m-3. The portion of biomass burning (BB%) was in opposite the highest 20% due to the city population migration to countryside and increased residential heating in a surrounding Moscow region. During the recovery period the 88% change of BC occurred with respect to lockdown. BCff component associated with emissions from fossil fuel (FF) combustion showed 100% increase. BB% dropped down to 13%, typical summer level. Decrease of traffic and industrial enterprise emissions during lockdown led to the change of BC daily and weekly trends. During the lockdown 2021 the mean BC increased despite a high number of pandemic cases. The absence of the impact of third wave COVID-19 response on black carbon showed the different levels of restriction strength implemented in the northern largest European megacity during various pandemic waves.