The air we breathe does not consist of gas molecules only: each cubic centimetre of atmospheric air typically contains thousands of small aerosol particles. These liquid or solid airborne particles originate from both natural sources (e.g. forests, oceans, deserts) as well as human activities (e.g. combustion processes, traffic), and their diameters span from nanometres to hundreds of micrometres.

Atmospheric aerosol particles play an important role in defining the environments we live in. When inhaled, many particles are harmful to human health. Atmospheric particles also decrease visibility and damage buildings and landmarks when deposited on their surfaces. On global scale, aerosols regulate the Earth’s energy balance and therefore the climate. In current climate models aerosols are still poorly represented: the Intergovernmental Panel on Climate Change recognizes aerosols as the largest individual source of uncertainty in calculations of the Earth’s radiative forcing.

My research focuses on understanding the sources, sinks and evolution of atmospheric aerosol particles and their interactions with clouds, climate and human health. My current focus is largely on the interactions between aerosol particles and the atmospheric gas phase, in particular the formation and effects of atmospheric organic aerosol and thus the feedback between ecosystems, human activities and climate.

Together with my colleagues, I work mainly with atmospheric computational models representing the processes governing the evolution and impacts of atmospheric aerosol populations. We model the evolution of atmospheric aerosol from the molecular to the global scale, with a tight connection to experimental data from both laboratory and field studies. The underlying philosophy is that to correctly upscale the molecular level processes to global scale, the scientists working on the fundamental theory need to be brought together with the scientists working on the highly simplified aerosol descriptions in regional and global atmospheric models.