European primary emissions of criteria pollutants and greenhouse gases in 2020 modulated by the COVID-19 pandemic disruptions
Authors: Guevara Marc , Petetin Hervé , Jorba Oriol , Denier van der Gon Hugo , Kuenen Jeroen , Super Ingrid , Jalkanen Jukka-Pekka , Majamäki Elisa , Johansson Lasse , Peuch Vincent-Henri , Pérez García-Pando Carlos 
Published: June 2022

Abstract. We present a European dataset of daily sector-,
pollutant- and country-dependent emission adjustment factors associated with
the COVID-19 mobility restrictions for the year 2020. We considered metrics
traditionally used to estimate emissions, such as energy statistics or
traffic counts, as well as information derived from new mobility indicators
and machine learning techniques. The resulting dataset covers a total of
nine emission sectors, including road transport, the energy industry, the
manufacturing industry, residential and commercial combustion, aviation,
shipping, off-road transport, use of solvents, and fugitive emissions from
transportation and distribution of fossil fuels. The dataset was produced to
be combined with the Copernicus CAMS-REG_v5.1 2020
business-as-usual (BAU) inventory, which provides high-resolution (0.1∘×0.05∘) emission estimates for 2020 omitting the impact of the COVID-19
restrictions. The combination of both datasets allows quantifying spatially
and temporally resolved reductions in primary emissions from both criteria
pollutants (NOx, SO2, non-methane volatile organic compounds – NMVOCs, NH3, CO, PM10 and
PM2.5) and greenhouse gases (CO2 fossil fuel, CO2 biofuel and
CH4), as well as assessing the contribution of each emission sector and
European country to the overall emission changes. Estimated overall emission
changes in 2020 relative to BAU emissions were as follows: −10.5 % for
NOx (−602 kt), −7.8 % (−260.2 Mt) for CO2 from fossil fuels,
−4.7 % (−808.5 kt) for CO, −4.6 % (−80 kt) for SO2, −3.3 % (−19.1 Mt) for CO2 from biofuels, −3.0 % (−56.3 kt) for PM10, −2.5 %
(−173.3 kt) for NMVOCs, −2.1 % (−24.3 kt) for PM2.5, −0.9 % (−156.1 kt) for CH4 and −0.2 % (−8.6 kt) for NH3. The most pronounced
drop in emissions occurred in April (up to −32.8 % on average for
NOx) when mobility restrictions were at their maxima. The emission
reductions during the second epidemic wave between October and December
were 3 to 4 times lower than those occurred during the spring
lockdown, as mobility restrictions were generally softer (e.g. curfews,
limited social gatherings). Italy, France, Spain, the United Kingdom and
Germany were, together, the largest contributors to the total EU27 + UK (27 member states of the European Union and the UK)
absolute emission decreases. At the sectoral level, the largest emission
declines were found for aviation (−51 % to −56 %), followed by road
transport (−15.5 % to −18.8 %), the latter being the main driver of the
estimated reductions for the majority of pollutants. The collection of
COVID-19 emission adjustment factors (https://doi.org/10.24380/k966-3957,
Guevara et al., 2022) and the CAMS-REG_v5.1 2020 BAU gridded
inventory (https://doi.org/10.24380/eptm-kn40, Kuenen et al., 2022b) have
been produced in support of air quality modelling studies.