This paper analyzes the effect of air masses of different types on the content of submicron aerosol particles in the lower 5 km atmospheric layer over Western Siberia. It is shown that in winter and spring Arctic air masses above the mixing layer contain a larger aerosol amount than mid-latitude air masses. In summer, the aerosol content in Arctic air masses is less practically within the entire altitude range. The main processes determining such character of differences have been discussed. The aerosol amount accumulated in the Arctic in different seasons has been estimated.