Dr. Otto Hänninen’s group has strong expertise in ambient air pollution research, in particular health impact assessment as well as exposure assessment. He has an extensive background in environmental exposure modelling. The overarching aim of his research is to understand significant processes leading to environmental health risks. He has contributed to different aspects of probabilistic modeling of personal exposures of a population, ranging from validation and evaluation of probabilistic microenvironmental exposure model against probability distributions of observed personal exposures to assessing infiltration of ambient air pollution, especially particles, to indoors. Currently, he is developing methods to analyze risk mitigation measures and to prioritize them based on their reduction potentials (effectiveness), costs, and perceptions.