Radon and its decay products in housing : estimation of the radon daughter exposure to the Swedish population and methods for evaluation of the uncertainties in annual averages

Abstract: Methods have been worked out for evaluation of the uncertainties due to temporal variations in the annual averages for the concentrations of radon-222 (radon) and radon daughters (RnD) indoors. These methods have been applied to the results from long-term measurements of radon in a few houses. The possible use of correction factors in order to get a more adequate annual average have also been studied and some examples have been given.On the basis of country-wide investigations carried out during 1955-56 and during 1972-75 averages of the radon concentrations in housing existing in 1950 and 1975 were calculated six years ago to be 29 and 71 Bq nr3 respectively. A new country-wide investigation with the aim of obtaining values representative for the country was carried out during 1980-82. On the basis of these results a new calculation was made of the concentrations in dwellings existing in 1975 to 101 Bq nr3 and also for the 1980 housing stock to 98 Bq rrr3. These results are discussed and the collective dose equivalents in the Swedish population have been calculated.