Indoor measurements of airborne natural radioactivity in Italy

A national survey to assess the indoor exposure of the Italian population is being carried out by ENEA with support from the Commission of the European Communities. Radon and decay products concentration meaurements are presented for dwellings located in different administrative districts, particularly in areas characterised by high values of terrestrial background. The activity concentrations of 226Ra and 232Th in some local building materials such as tuff and pozzolana, sampled in such areas, were found to be higher than the ones occurring in other materials used on a country wide scale. The results of an active survey of 50 dwellings sampled in a volcanic area have also shown significant levels of 220Rn daughter concentrations. A passive survey of a large sample of about 500 houses has provided a preliminary picture of the indoor exposure of the Italian population according to different administrative districts and building materials. (author)