The results of spectral aerosol optical depth (АОD) measurements obtained in 1999, 2003, and 2004 are analyzed. These periods were characterized by a significant increase of the atmospheric turbidity due to forest fire smokes near Tomsk, as well as the arrival of remotely transported air masses. The measurements were carried out with the multi-wavelength sun photometer (λ = 0.35-4.0 μm). The dynamics of daily averaged AOD values in conditions of the smoke presence in the atmosphere for several days, as well as the corresponding transformation of the aerosol microstructure are treated based on results of solution of the inverse problem.