A series of smoke experiments in the Big Aerosol Chamber (BAC) on studying the dynamics of variations of smoke aerosol polarization characteristics was conducted; their microphysical changes in the process of relaxation and disintegration were estimated. It has been shown that the specificity in formation of the fine-dispersed smoke component depends not only on the mass of a coniferous wood sample, but also on the residence time of the aerosol-gas mixture inside the thermal decomposition chamber (TDC) (muffle furnace). The increase of sample masses leads to growing "coagulation" losses of small particles (r < 0.2 microns). The active formation of the moderate-dispersed fraction favors more effective cleaning of the air medium from finely dispersed aerosols, including the nanometer range of the particle size. Particles of pyrolysis smoke generated at low temperatures (T ~ 300°С) represent mainly aerosols, which poorly absorb the visible radiation. Estimations show that the values of a real part of the refractive index n vary within 1.52-1.58. In this case, the sought minimum of the regularizing functional is commonly achieved at values of the imaginary part of the complex refractive index χ ~ 0.001.