This paper presents the results of the analysis of nephelometric data obtained during long-term airborne and ground based observations in the lower troposphere over Western Siberia. It order to study variability of submicron aerosol characteristics in more detail, separate analysis has been carried out of the coefficients of scattering of dry aerosol substance σ d( H) and of the condensation activity parameter γ. Some thermo-optical characteristics of the aerosol obtained at a controlled heating up to 250°C are also considered. Annual behavior of the total aerosol content at the heights up to 5 km is described as well as seasonal peculiarities in the aerosol stratification, σ d( H) Seasonal differences in the values of the condensation activity parameter and thermo-optical characteristics are discussed.