Estimation of indoor 222Rn and 220Rn concentration and annual inhalation dose in the indoor environment around Kolar district of Karnataka state, India

The indoor 222Rn and 220Rn were measured by using deposition progeny sensors and single-entry pinhole dosimeter around Kolar Gold Fields of Karnataka state, India. The thirty different places were identified and fixed the dosimetry cups for the determination. The 222Rn and 220Rn concentrations of indoor environment range from 26.2 ± 1.3 to 138.4 ± 1.6 and 21.2 ± 0.8 to 133.3 ± 1.5 Bq/m3 with a mean value of 68.8 ± 1.6 and 61.8 ± 1.5 Bq/m3, respectively. The equivalent concentrations of 222Rn and 220Rn values vary from 0.9 ± 0.4 to 7.6 ± 1.1 and 6.8 ± 0.8 to 19.8 ± 1.8 Bq/m3 with a standard value of 4.3 ± 0.8 and 14.2 ± 1.3 Bq/m3, respectively. The values between the equilibrium factor between 222Rn, 220Rn, and their daughter were also calculated and found to be 0.23 and 0.07, respectively. The average annual intake of 222Rn, 220Rn, and their daughters' products is 2.28 mSv/y1, slightly below the global average of 2.4 mSv/y1 from all components. The data obtained compare average values in the world.