Guus Velders is a professor of air quality and climate interactions at Utrecht University (Netherlands) and senior scientist at RIVM, the National Institute for Public Health and the Environment, Bilthoven, the Netherlands. He works on modelling of the ozone layer depletion, climate change, and air quality at various scales. He is involved in both scientific research and policy assessments on the national, European and global scale. He was coordinating lead author of a 2007 IPCC special report and of various UNEP/WMO scientific assessment panel reports (1998, 2006, 2010, 2018, 2022). The last ten years he was responsible as project leader for the annual large-scale air quality and nitrogen deposition maps. This work is highly relevant for policy makers and society and involves interaction with several Dutch ministries. Since 2006 he collaborated intensively with colleagues in the USA on the benefits of the Montreal Protocol for climate and the role of replacement compounds (hydrofluorocarbons) on climate. This work was very successful, both with respect to publications and because it was at the basis of the 2016 amendment of the Montreal Protocol. He is recipient of the UNEP Montreal Protocol ozone award for scientific leadership 2017; selected as Nature's 10: Ten people who mattered in 2016; selected as The 100 most influential people in the world (TIME magazine, 2016); awarded the Scientific and Technological Achievement Award (US EPA, 2008). He is co-chair of the Expert Panel on Clean Air in Cities under the UNECE Convention on Long Range Transboundary Air Pollution.

Research fields:

• Air quality: modelling gases and aerosols, biomass use, effects climate change
• Ozone layer depletion: relation with climate change, scenarios CFCs and hydrofluorocarbons (HFCs)
• Scenarios studies and effects policy options