Mathias Cehlin, Ph.D., is an Associate Professor in Energy Systems at University of Gävle in Sweden. He is Co-Director for the strategic research area Urban Sustainability at University of Gävle, which aims to contribute to an urban sustainable development that improves people's living environment and health. Cehlin is also Co-Director for the research program Urban Transition and Program Director for the industrial post-graduate school Resource-efficient Energy Systems in the Built Environment, Reesbe, which involves 20 PhD students and around 20 companies in the field of energy systems. Cehlins current research projects include energy-efficient buildings, indoor and outdoor air quality, and resilient cooling. He has written multiple successful grants funded by e.g. the Swedish Knowledge Foundation and the Swedish Research Council Formas.