Aerosol Particle Formation in Different Types of Air Masses in Hyytiälä, Southern Finland

Abstract

We analyzed synoptic weather maps and satellite images over Scandinavia for the period of 2003-2005 in order to reveal in which types of air masses the new particles formation occur more frequently in Hyytiala, southern Finland. We calculated monthly number of different types of air masses (Arctic, Polar, and Subtropical) and the frequency of different types of air masses for the days classified according the intensity of new particle formation. The results show that for all seasons Arctic air masses bring most favorable condition for aerosol particle formation in boreal forest. In about 40% of arctic air surges new particles are registered at Hyytiala. We also calculated the median particle concentration for three different modes (nucleation, 90 nm) in Arctic, Polar, and Subtropical air masses during the days when no frontal passages have been observed over Hyytiala.