Gregor Kiesewetter is a senior research scholar in the Pollution Management research group of the Energy, Climate, and Environment Program at the International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria. He earned his PhD in atmospheric physics from the University of Bremen, Germany, in 2011. At IIASA he has been responsible for developing the ambient air pollution and health impact calculations in the GAINS model, contributing to policy assessments at various scales from local to global. Gregor currently serves as a member of the Global Air Pollution and Health Technical Advisory Group to the World Health Organization.