Estimation of radiological dose due to radon, thoron and their progeny in indoor atmosphere of Shivamogga district, Karnataka, India

This study reports the Rn-222, Rn-220, and their progeny concentration in Shivamogga district by using SSNTD's based pin hole dosimeters and deposition-based progeny sensor. The average indoor Rn-222 and Rn-220 concentration varies from 8.14 to 146 Bq m(-3) and 13.01 to 157 Bq m(-3) with a mean value of 60.61 and 61.77 Bq m(-3). The EEC for Rn-222 and Rn-220 ranges from 1.55 to 19 Bq m(-3) and 0.44 to 6 Bq m(-3) with a mean value of 7.29 and 2.66 Bq m(-3). The annual average equilibrium factor for Rn-222 is well within the global mean values of 0.4, while the thoron is bit higher than specified global mean values of 0.02. The annual effective dose varies from 0.31 to 2.5 mSvy(-1) with a mean value of 1.1 mSvy(-1).