Analysis of particle size distribution changes between three measurement sites in Northern Scandinavia

Measured aerosol size distributions from three measurement stations and modeled air mass trajectory data were combined to study aerosol dynamics in the boreal forest zone in Northern Scandinavia. Three approaches were used: investigation of new particle formation events, analysis of air masses arriving from ocean to continent, and study of changes in the aerosol size distributions when air masses travel from one measurement site to another. The statistical analysis of air masses travelling either from the Atlantic Ocean to measurement sites or from one site to another showed that on average the condensational growth was present during the summer season, and it was not restricted only to the days when evident new particle formation was observed. The rate of this average apparent growth of particle diameter was 3-7 times smaller than the growth rate of nucleation mode particles during the new particle formation events.