Survey of Radon in Australian residences

Fifty Australian buildings of five different types (earth-covered, earth-sheltered, earth-walled, those ‘dug out’ of self supporting rock, and above-ground dwellings), are currently being surveyed for radon activity. Using nuclear track detectors over a one-year period, 14 of these sites so far returned have yielded a highest level of 388 Bq m^ 3 (interior air, earth-wail house) and a lowest level of 19 Bq tn^ 3 (standard above-ground cavity-brick house). Present trends indicate that: (i) a problem of high levels exists in some earth-wall and dugout dwellings which, if uranium mine data are extrapolated, could indicate some increased risk of lung cancer; (ii) when ventilation rate is other than minimal, it does not appear to affect radon concentration in the expected direct inverse way.