Characterization of indoor airborne radioactivity

Preliminary measurements, using both grab sampling and continuous method, have been carried out in a typical Australian home. Good agreement was obtained between the two sampling methodologies. The measured F values were in the range of 0.17 to 0.49, with values for the mean and standard deviation for the grab-samples and the continuous sampling of 0.28 +- 0.06 and 0.32 +-0.09, respectively. The values for the unattached fraction (fP) of potential alpha energy concentration (PAEC) were in the range of 0 to 80%. The day time mean value of fp was 14% for both methods. The measured PAEC size distributions were either single-peaked or bimodal, with the geometric mean of the lower mode between 0.5 and 1.2 nm and the upper mode between 85 and 200 nm. Factors for conversion to effective dose were calculated from the measured results, with mean and geometric mean of 22.5 and 19.5 Bq · m-3 per mSv, respectively. These results are consistent with similar measurements in the European homes