Correlations between local geology and radon concentration in dwelling-houses

In the past decade many international studies have established that the radioactive gas radon is responsible to a large extent for the total radiation dose absorbed by the population. Since in Switzerland the knowledge about the radon problems was very scarce, detailed investigations were needed. For this reason the Swiss Federal Health Office started and sponsored a research program called RAPROS (Radon Programm Schweiz) with the aim of assessing some aspects of radon exposure in Switzerland. The project RAPROS 4.1.2 ''Radon and geology/water'' is the topic of this Ph.D. thesis. The investigation of the relationship between local geology and indoor radon concentrations was a new research field in Switzerland. By choosing characteristic but limited geologic settings, the plan of this program was to obtain data and knowledge that could then be extended to larger regions of Switzerland. The main objective of this Ph.D. work was however the identification of localities with high radon risk. Adapting experience acquired in other countries to the geological conditions in Switzerland led to the choice of seven areas for detailed investigations: Dierikon (LU), Udligenswil (LU) and Sempach (LU) in the Swiss plateau; Schmitten (GR), Vicosoprano (GR), the Muenster valley (GR) with Tschierv, Fuldera and Valchava, Siat (GR) and Bosco Gurin (TI) in the Alps, and La Sagne (NE) in the Jura mountains. (author) figs., tabs., 99 refs