Natural Radioactive Aerosols in the Groundlevel Air of a Czechoslovak Locality With Respect to the Radiological Exposure of Its Population

Abstract

The concentration of natural radioactive aerosols carrying the decay products of radon and thoron was studied by taking samples daily at Plzen, Czechoslovakia, during two sampling periods, 1957–1958 and 1959–1960, by the filtration method. The extrapolated radon concentration indicated a great dependence on the meteorological factors as was especially evident in the dry weather period of 8 weeks in 1959. The radon and thoron concentrations gave valuable information on the problem of the annual course of radon and thoron in the atmosphere. The absorbed dose-rate from the inhalation of the decay products of radon and thoron was estimated from Hultqvist's expressions. At the average radon concentration in the groundlevel air, 0.106 pc/l., the absorbed dose-rate in the lungs caused by the decay products of radon is 53 mrem/year. The average value of radon concentration at Plzen and the estimated value of the absorbed dose-rate by inhalation are among the lowest of the usual values reported by other authors in various countries. Finally, the external whole-body gamma dose-rate from the decay products of radon was estimated by the method of Hultqvist and independently by the method Of Stukkenberg; similar results, namely 1.51 and 1.80 mrad in a year, were obtained.