Radon measurements in soil to predict indoor radon concentrations in new buildings in an area with unusually high radon levels

We investigated the possible correlation between measurements of radon concentrations in soil and indoor radon concentrations. Such a correlation could be used to estimate the radon concentrations to be expected in new buildings, which is important for the evaluation of building plots. For this purpose, we measured the seasonal course of radon concentrations in 41 tubes along two profiles in an area with unusually high radon levels (Umhausen, 2600 inhabitants, Tyrol, Austria). Parallel to the measurements in the tubes, radon concentrations were measured in the basements of 30 houses located within a radius of 15 m around the tubes in July 1992 and in February 1993. Linear correlation analysis was performed to establish the correlation between the indoor measurements and the measurements in the tubes. Measurements of radon concentrations in soil give only limited information about the radon concentrations to be expected in new buildings, and seasonal and local variations make predictions based on spot measurements unreliable.