Based on the previous results obtained in an integral reactor with fixed bed, active soda of the 1st generation (NaHCO₃ precursor) was chosen for the detailed study oi reactivity in fluidized bed. The experiments in fluidized bed represent the scale extension by 3 orders of magnitude and a considerable approach to the situation in a practical application. The main factors affecting the mean degree of S0₂ and nitrogen oxides removal are SO₂/NO_X in gaseous phase, water vapour content, temperature, normalized stoichiometric ratio (NSR), average residence time of gas in fluidized bed, and particle size. At stoichiometric ratio unity (NSR = 1), the mean degree of S0₂ and NO_X removal was found more than 70 % and 40 %, respectively. Also microstructure was investigated by SEM and chemical composition of solidphase surface was determined by ESCA. The results obtained are promising with respect to NaHCO₃ applied in the cleaning of flue gas from solid-waste incinerators.