By means of sampling of radioactive aerosols in BYPASS System it have been shown that in April, 2008 considerable changes of concentration during the operation of Modernized System of Dust Suppression (MSDS).were not observed. Such situation probably is conditioned by the presence of polymer film at the cover of a disintegration of Central Hall and in buttress area. However external environment heavy winds result in rising of aerosol concentration in BYPASS System due to a dust raising in apartments out of MSDS service area.