RESULTS OF THE REPRESENTATIVE ITALIAN NATIONAL SURVEY ON RADON INDOORS

A representative national survey on population exposure to radon in It alian dwellings was carried out from 1989 to 1994, with the co-operati on of the National Health Service, The measurements were performed by 19 Regional Laboratories, all using the same techniques and protocols, A stratified, two-stage sampling procedure was used to sample familie s, The sampled families were approached door-to-door to maximize respo nse. To optimize the quality of the measurements, two dosimeters, each containing two alpha track detectors, were placed together in one roo m (typically the bedroom) for two consecutive 6-mo periods, The distri bution of annual radon concentration was derived from measurements in 4,866 dwellings. The average value is 75 Bq m(-3) and the fractions of dwellings above the reference levels of 150, 200, 400, and 600 Bq m(- 3) are 8.7%, 4.7%, 1.0%, and 0.2%, respectively. The geometric mean is 57 Bq m(-3) while the geometric standard deviation is 2.0. The averag e values in the Italian Regions fall within the 20-120 Bq m(-3) range, When the average radon concentration is examined vs, story, building materials seem to play a significant role, The average lifetime risk o f lung cancer for chronic radon exposure of Italian population at home would be about 5x10(-3), using the risk factor proposed by the ICRP i n 1993.