The Aerosol-Cloud-Climate Interactions -group (ACCI) operates within the Institute for Atmospheric and Earth System Research (INAR, University of Helsinki), belonging to the Centre of Excellence in Atmospheric Science - From molecular and biological processes to the global climate. We investigate the sources and processes modifying atmospheric aerosol populations, interactions between aerosols, clouds and radiation, and the associated feedback mechanisms. We make analyses and parameterisations from local to global scale by applying data from field and laboratory measurements, ground-based and satellite remote sensing, as well as from modelling activities.