The varibility in atmospheric aerosol (AA) concentrations is considerable even at rural background stations with suppressed direct anthropogenic influence (Zíková & Ždímal, 2013), and strongly depends, among other meteorological parameters, on wind speed and direction. The wind direction, however, gives only limited information on the air masses origin, so the more detailed analysis of air mass trajectories was done to describe the variability of the AA at the Košetice station.