Indoor radon concentrations: The influence of geological factors in Italian study case

The indoor radon exposition is internationally known as an health hazard. For this reason, many countries have introduced specific laws and regulations and radon-risk maps have been consequently produced. In Italy the radon exposure legislation regards only general workplaces (D. Lgs. n. 241/00) and only one national survey in the 90’s has been currently conducted by APAT, ISS and ARPA regional agencies. This survey assessed the exposure to indoor radon concentration in national dwellings on large scale. In absence of guidelines, only few Italian Regions have prepared a surveying protocol using independent standards in order to identify “radon prone areas”, inducing a bigger uncertainty on the definition of a national risk map. In the present work a standardized methodology for indoor radon measurements has been set up, with attention to the development of a passive measurement technique, validated through a comparison with other international laboratories. Data from a wide sampling (Lombardia, with the case studies of Milano Province and Milano city, Emilia Romagna, Toscana, Puglia) of radon indoor monitoring has been elaborated and georeferenced, using geo-statistical technique, to produced a map of annual average radon concentration and to verify the relapse of seasonal fluctuations on radon concentrations. Appling the recently introduced international approach, the elaborated maps has been integrated with geological knowledge of highest concentration macro-areas identified in order to better determine them. This study allowed to point out not negligible radon concentrations also in traditionally no–risk zone; moreover the application of the developed methodology will be useful to give advices to fill legislation gaps or to draft urban development plans