Professor Mark Sutton is an environmental physicist based at the UK Centre for Ecology & Hydrology (UKCEH) Edinburgh, and an Honorary Professor at the University of Edinburgh. An expert on atmospheric ammonia, he leads international research activities on nitrogen at the science–policy interface. He is Director of the UNEP/GEF International Nitrogen Management System (INMS), and the UKRI Global Challenges Research Fund’s South Asian Nitrogen Hub (SANH).