[en] Important incoherence exists in literature on the effective thickness δ of the boundary layer across which aerosol particles are deposited by Brownian concentration diffusion onto walls. Values of 1 micrometer up to several centimeters are reported. The rate of deposition of particles smaller than 0.1 micrometer will be greatly influenced by diffusive transport through this boundary layer, the rate of which is inversely proportional to δ. Consequently, a reevaluation of the literature data in the light of new experimental information is worthwhile. New experimental data from ECN on stirred diffusive deposition in the size range from molecular up to 0.3 micrometers reveals that δ is proportional to Dⁿ (D = diffusion coefficient of the particles) with n = 0.27. This agrees with Fuchs theory giving n = 0.25. The conflicting literature data on δ (which are too small as a rule) are discussed. From the obtained relation it can be shown that non-stirred diffusive aerosol deposition is unrealistic. It is concluded that stirred diffusive deposition plays a minor role in removal of the aerosol mass from post accident nuclear atmospheres