Indoor Radon and Thoron Surveys in High Radioactivity Areas of Italy

This paper reports preliminary results of regional and local surveys of indoor radon carried out in about 800 houses located in Alto Lazio and in the Rome district. Results of a passive survey of indoor radon concentrations are presented. Measurements were carried out using CR-39 alpha track detectors (ATD). The houses tested were selected using criteria so as to be representative of the housing stock of the areas investigated. Data sets are analysed on the basis of the main construction material (tuff and brick buildings) and the floors of the rooms tested. Results of local active surveys of indoor radon and thoron progeny in 14 locations of Alto Lazio are also reported. Simultaneous measurements were made of radon and thoron progeny indoor concentrations at different floors to test correlations and modelling concentrations. This study demonstrates that in particular areas PAEC 220Rn makes a significant contribution to the lung dose of inhabitants.