Prof. Markku Kulmala is a world-class leader in the field of atmospheric aerosols and one of the founders of the «meteorology of land ecosystems». His work encompasses the experimental and theoretical physics of aerosols, atmospheric chemistry, observation meteorology, biophysics, in particular, biosphere-aerosol-cloud-climate interactions and reverse relations as well as interactions between the air quality and the climate. The main academic goal was to reduce the scientific uncertainty with respect to problems of the global climate change, especially related to aerosols and clouds. He emphasised biogenic mechanisms of the formation of aerosol particles and their relation with problems of the interaction between the biosphere and the atmosphere, biogeochemical cycles as well as the role of trace gases in the chemistry of the atmosphere. To sole these interdisciplinary problems, Prof. Kulmala has created a complex research programme that includes continuous long-term observations of the atmosphere, the global modelling and deep theoretical and experimental understanding of the dynamics of atmospheric clusters and aerosols. In his pioneering research, Markku Kulmala works at levels from the monomolecular and the molecular to the global scale.