Measurement of indoor radon–thoron concentration and radon soil gas in some North Indian dwellings

• Indoor radon–thoron concentration was measured by twin cup dosimeter.
• Radon soil gas at depth of 50 cm was measured by calibrated cup.
• The weak correlation is found between indoor radon and soil gas concentration.

The indoor radon, thoron and their decay products are the main contributors of total inhalation dose in the living environment. Radon soil gas concentration is about thousand times higher as compared to environment. Thus, it is necessary to measure indoor radon–thoron and radon soil gas underneath the soil. Keeping this in mind the measurements of radon and thoron in the indoor environment in some parts of Northern Haryana, India were carried out using twin cup dosimeters along with radon soil gas underneath the soil. The calibration factor for these dosimeters was measured during repeated experimental exercise and verified for two different depths. The radon and thoron concentration in the dwellings varied from 17 to 51 Bq/m3 and 9 to 73 Bq/m3, while the radon soil gas varied from 2.80 kBq/m3 to 6.46 kBq/m3. The radon soil gas and indoor radon–thoron concentration strongly depend upon the geological formations. A good correlation was found between the indoor radon and thoron concentration for mud houses.