Measurement of radon, thoron and their progeny in different types of dwelling in Almora District of Kumaun Himalayan Region

The indoor concentrations of radon (²²²Rn), thoron (²²⁰Rn) and their daughter products were measured in the dwellings of Almora district in Kumaun Himalaya, India using pin-hole dosemeters and deposition progeny sensors. The measurements were made in the residential houses built of mud, stone with cement plaster and cemented house during winter season. Average [geometric mean (GM) values] radon and thoron concentrations for all dwellings were found to be 99.82 and 79.70 Bq m^-3, respectively, while average equilibrium equivalent radon concentration and equilibrium equivalent thoron concentration (measured for the first time for this region) were measured at 35.22 and 2.52 Bq m^-3, respectively. Radon concentration (GM values) was found to be 110.73, 97.00 and 93.85 Bq m^-3 for mud houses, stone with cemented plaster houses and cemented houses, respectively. On the other hand, thoron concentration values were 87.10, 75.79 and 75.68 Bq m^-3 for cemented houses, mud houses and stone with cemented plaster houses, respectively. Interpretations have been made on the basis of measured radon/thoron and progeny concentration values with respect to the difference of construction material of the dwellings. (authors)