In this paper we present analysis of the annual behavior of the vertical profile of scattering coefficients of the dry matter of submicron aerosol particles. Experimental data analyzed have been obtained from nephelometric airborne sounding of the atmosphere over West Siberia in 1986-1988. Sounding was carried out at altitudes from 0 to 5 km . It is shown in the paper that in spring time there was observed an enhanced atmospheric turbidity at altitudes above 2 km, that was caused by the long-range transport of aerosol produced in the western regions of Siberia after snow thawing. We also consider in this paper the variability of the vertical profile of aerosol content for four seasons. Based on data on mean temperature of the low atmospheric layers we propose an empirical formula for estimating the mixing layer height. Annual behavior of the mixing layer height is analyzed.