The uncertainty associated with climate change is rooted in our limited understanding of molecular scale processes occurring in aerosol particles, droplets and ice crystals, which affect cloud properties and their climate impacts via modulating particle formation and growth. Formation, growth, atomistic scale properties of particles and their interactions with the surrounding vapour phase are associated with temporal and spatial scales that are attainable only by a handful of techniques. The recent emergence of single particle experiments (optical tweezers) and molecular simulations (quantum chemistry methods, molecular dynamics and Monte Carlo) as tools to characterise atmospheric aerosol on single particle level has provided unique insights to aerosol processes from new particle formation to activation as ice or cloud droplets. We welcome nanoscale observations of processes involving aerosol particles based on both experiments and molecular simulations which address nanoscale structure, single particle processes, chemical reactions within the particle or any related topic.