Dr. Matthias Karl has been a Researcher at the Helmholtz-Zentrum Hereon since 2015. Before that, he served as a Researcher/Project Manager at the Norwegian Institute for Air Research (NILU) from 2008 to 2015, and a Post-Doctoral Researcher at the European Commission from 2005 to 2008. He obtained his doctoral degree in Geography at the University of Münster (Faculty for Mathematics and Sciences) in 2004 and his master's degree in Geoecology (Environmental Sciences) from the University of Bayreuth in 1997. His research interests are the atmospheric transformation and dispersion of aerosol particles emitted from combustion and mobile transport sources; chemistry transport models on the urban scale for gases and aerosols; and exposure to air pollution and health effects.