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Ozone Anomalies in the Free Troposphere during the COVID-19 Pandemic
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  • Idir Bouarar,
  • Benjamin Gaubert,
  • Guy P. Brasseur,
  • Wolfgang Steinbrecht,
  • Thierno Doumbia,
  • Simone Tilmes,
  • Yiming Liu,
  • Trissevgeni Stavrakou,
  • Adrien Michel Deroubaix,
  • Sabine Darras,
  • Claire Granier,
  • Forrest Gerhart Lacey,
  • Jean-François Müller,
  • Xiaoqin Shi,
  • Nellie Elguindi,
  • Tao Wang
Idir Bouarar
Max Planck Institute for Meteorology
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Benjamin Gaubert
National Center for Atmospheric Research (UCAR)
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Guy P. Brasseur
Max Planck Institute for Meteorology

Corresponding Author:[email protected]

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Wolfgang Steinbrecht
Deutscher Wetterdienst
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Thierno Doumbia
Laboratoire d'Aerologie, University de Toulouse, CNRS, UPS
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Simone Tilmes
National Center for Atmospheric Research (UCAR)
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Yiming Liu
Sun Yat-sen University,
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Trissevgeni Stavrakou
Royal Belgian Institute for Space Aeronomy
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Adrien Michel Deroubaix
Max Planck Institute for Meteorology
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Sabine Darras
Observatoire Midi-Pyrenees
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Claire Granier
University of Toulouse
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Forrest Gerhart Lacey
National Center for Atmospheric Research
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Jean-François Müller
Royal Belgian Institute for Space Aeronomy (BIRA-IASB)
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Xiaoqin Shi
Max Planck Institute for Meteorology
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Nellie Elguindi
Centre national de la recherche scientifique
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Tao Wang
The Hong Kong Polytechnic University
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Abstract

Using the CAM-chem Model, we simulate the response of chemical species in the free troposphere to changes in emissions of primary pollutants during the COVID-19 pandemic. Zonally averaged ozone concentrations in the free troposphere during Northern Hemisphere spring and summer were 5 to 15 % lower than 19-year climatological values, in good quantitative agreement with ozone observations. About one third of this anomaly is attributed to the drastic reduction in air traffic during the pandemic, another third to reductions in surface emissions, the remainder to 2020 meteorological conditions, including the exceptional springtime Arctic stratospheric ozone depletion. The overall COVID-19 reduction in mean northern hemisphere tropospheric ozone in June is less than 5 ppb below 400 hPa, but reaches 8 ppb at 250 hPa. In the Southern Hemisphere, COVID-19 related ozone reductions by 4 to 6% were masked by comparable ozone increases due to other changes in 2020.
28 Aug 2021Published in Geophysical Research Letters volume 48 issue 16. 10.1029/2021GL094204