The inaugural ACP Paul Crutzen Publication Award

29 September 2022

The ACP Paul Crutzen Publication Award was created to recognize an outstanding publication in ACP that advances our understanding of atmospheric chemistry and physics. The annual award was created in honour of Paul Crutzen, Nobel Prize awardee and former director of the Max Planck Institute for Chemistry, who played a pivotal role in the creation of the journal 21 years ago.

This year's recipient for a paper published in 2021 is

Global impact of COVID-19 restrictions on the surface concentrations of nitrogen dioxide and ozone
Christoph A. Keller, Mathew J. Evans, K. Emma Knowland, Christa A. Hasenkopf, Sruti Modekurty, Robert A. Lucchesi, Tomohiro Oda, Bruno B. Franca, Felipe C. Mandarino, M. Valeria Díaz Suárez, Robert G. Ryan, Luke H. Fakes, and Steven Pawson
Atmos. Chem. Phys., 21, 3555–3592,,, 2021

COVID-19 was the major event of 2021 and presented a unique opportunity to understand the effects of widespread reductions in air pollutant emissions. However, the effects were short-lasting, which makes them very challenging to separate reliably from the large variability in meteorology. In a very effective application of machine learning, Keller et al. achieved this separation for thousands of observation sites in 46 countries. The results reveal reductions in nitrogen dioxide concentration of as much as 60 %, but a much more complex response of ozone concentrations that depend on season, timescale, and environment. The results provide a unique dataset to test our understanding of atmospheric chemistry and to predict future reductions more reliably in ozone pollution as nitrogen dioxide emissions decline.

The prize publication was selected by an independent committee with members Annica Ekman (Chair, Stockholm University), SK Satheesh (Indian Institute of Science, Bangalore), Susan Solomon (MIT), Steve Sherwood (University of New South Wales), John P. Burrows (University of Bremen), Ulrike Lohmann (ETH Zurich), Sonia Kreidenweis (Colorado State University), and Hiroshi Tanimoto (National Institute for Environmental Studies, Japan).