The behavior of radon daughters in the domestic environment: Effect on the effective dose equivalent

Simultaneous measurements of the radon daughter concentrations, the ventilation rate and the size distribution of the inactive aerosol have been performed in two bedrooms, a living room and a cellar. The measured radon daughter concentrations were fitted by the room model to optimize the deposition rate of the unattached daughters. The mean value was 18/h in the rooms and 8/h in the cellar. Then the unattached fraction was calculated in each measurement and was found to be between .05 and .15 without aerosol sources in the room and below .05 in the presence of aerosol sources. The effective dose equivalent was computed with the Jacobi-Eisfeld model and with the James-Birchall model and was more related to the radon concentration than to the equilibrium equivalent radon concentration. On the basis of the authors' analysis a constant conversion factor per unit radon concentration of 5.6 (nSv/h)/(Bq/m/sup 3/) or 50 (μSv/y)/(Bq/m/sup 3/) was estimated