RESUMO
This work is related to the problem of providing a more careful evaluation of the population exposure to natural radiation background, and was carried out in connection with the ENEA programmes on the assessment of indoor exposure doses in Italy. A large number of works in recent years have pointed out the main contribution of the indoor dose to the natural dose received by the members of the general population, and the large contribution of radon daughter inhalation. Different building materials and techniques lead to different exposure doses. In Milano such materials can be quite different in kind (bricks, concrete, gypsum by-products, tile-stone, paving-tile, etc.) and origin (national and foreign). For this reason, a collection of indoor doses in Milano is not only complementary to analogous investigations carried out in other Countries of the European Communities, but the obtained information can be compared with other large European towns. As agreed, a large number of various dwellings in Milano were investigated to evaluate the external gamma-ray exposure rate, and measurements of indoor radon concentrations were performed for some of them. Various typical building materials used in Lombardia were also analysed by means of gamma-ray spectrometry.
