Natural radioactivity and radon exhalation in stony materials

Recently, radon sources have been a matter of concern, as high levels have been measured in some houses. This work contributes to the assessment of radon exhalation from those stones which are mostly used for building materials. The first part of this paper concerns measurements of natural radionuclide concentrations (238U,232Th) in building materials by means of gamma-spectrometry. The second part deals with the determination of stone exhalation rate using a particular instrument, called an ‘emanometer’, designed and developed at our institute. As a general result, this research indicates that the radon exhalation is determined more by the peculiar characteristics of the building material than by its specific content of radium.