A method to evaluate the contribution of building material to indoor gamma dose rate through outdoor measurements: preliminary results.

Building materials can be an important source of exposure to gamma radiation indoors. In situations in which it is impossible to enter the dwellings to measure indoor gamma dose rate, as can happen in epidemiological studies and in surveys on randomly selected dwellings, it is important to obtain accurate and precise estimates of the indoor gamma dose rate. In this paper, preliminary results of a validation study of a new method, named IN-OUT, to estimate the indoor gamma dose rate attributable to the building materials are presented. This method, which is still in progress, is based on outdoor measurements, performed close to an external wall of a dwelling, and on a 'room model' elaboration, which takes into account geometrical and structural characteristics of the dwelling. The validation was performed using data--relevant to 91 dwellings, at present--collected in Latium and Campania within the framework of 'SETIL', the Italian epidemiological study on the aetiology of childhood leukaemia, lymphoma and neuroblastoma.