Estimates of the dose of radon and its progeny inhaled inside buildings

The concentration of radon in the air in buildings ranged from 1.87 ± 3.24 Bq/m3 to 14.27 ± 1.50 Bq/m3 with a mean of 6.31 ± 3.47 Bq/m3 while that of the progeny of radon varied from 0.007 to 0.057 WL (average: 0.025). The mean indoor concentration of radon was considerably less than the lower levels prescribed by EPA (148 Bq/m3), WHO (100 Bq/m3), EEC (400 Bq/m3), ICRP (200–600 Bq/m3) and NRPB (200 Bq/m3). The annual effective equivalent dose of indoor radon (< 0.8 mSv/y) that the bronchial and pulmonary regions of human lungs are exposed to (<0.8 mSv/y) is less than the UNSCEAR and WHO recommended global lower average dose value of 1 mSv/y. The lifetime fatality risk of exposure to the progeny of radon (PAEC) varied from 0.03 × 10−4 to 0.19 × 10−4, with an average value of 0.08 ± 0.04 × 10−4.