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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
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© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

  16 Nov 2020

16 Nov 2020

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This preprint is currently under review for the journal ACP.

COVID-19 lockdowns highlight a risk of increasing ozone pollution in European urban areas

Stuart K. Grange1,2, James D. Lee2, Will S. Drysdale2, Alastair C. Lewis2,3, Christoph Hueglin1, Lukas Emmenegger1, and David C. Carslaw2,4 Stuart K. Grange et al.
  • 1Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
  • 2Wolfson Atmospheric Chemistry Laboratories, University of York, York, YO10 5DD, United Kingdom
  • 3National Centre for Atmospheric Science, University of York, Heslington, York, YO10 5DD, United Kingdom
  • 4Ricardo Energy & Environment, Harwell, Oxfordshire, OX11 0QR, United Kingdom

Abstract. In March 2020, non-pharmaceutical interventions in the form of lockdowns were applied across Europe to urgently reduce the transmission of SARS-CoV-2, the virus which causes the COVID-19 disease. The near-complete shutdown of the European economy had widespread impacts on atmospheric composition, particularly for nitrogen dioxide (NO2) and ozone (O3). To investigate these changes, we analyze data from 246 ambient air pollution monitoring sites in 102 urban areas and 34 countries in Europe between February and July, 2020. Counterfactual, business as usual air quality time series are created using machine learning models to account for natural weather variability. Across Europe, we estimate that NO2 concentrations were 34 and 32 % lower than expected for traffic and urban-background locations while O3 was 30 and 21 % higher (in the same environments) at the point of maximum restriction on mobility. The European urban NO2 experienced in the 2020 lockdown was equivalent to that which might be anticipated in 2028 based on average trends since 2010. Despite NO2 concentrations decreasing by approximately a third, total oxidant (Ox) changed little, suggesting that the reductions of NO2 were substituted by increases in O3. The lockdown period demonstrated that the expected future reductions in NO2 in European urban areas are likely to lead to a widespread increase in urban O3 pollution unless additional mitigation measures are introduced.

Stuart K. Grange et al.

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Stuart K. Grange et al.

Stuart K. Grange et al.


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Latest update: 24 Nov 2020
Publications Copernicus
Short summary
The changes in mobility across Europe due to the COVID-19 lockdowns had consequences for air quality. We compare what was experienced, to estimates of what would have been without the lockdowns. Nitrogen dioxide (NO2), an important vehicle-sourced pollutant, decreased by a third. However, ozone (O3) increased in response to the lower NO2. Because NO2 is decreasing over time, increases in O3 can be expected in European urban areas and will require management to avoid future negative outcomes.
The changes in mobility across Europe due to the COVID-19 lockdowns had consequences for air...