Studies on indoor radon/thoron and their progeny levels at Mysore city, Karnataka state

Abstract

Radon, thoron and their progeny concentrations have been measured in different types of buildings at different locations in Mysore city over a period of 2 years using solid state nuclear track detector (SSNTD) method. The dose to the selected population of Mysore city has been estimated. The arithmetic mean (AM) values of concentrations of radon and thoron in indoor atmosphere ranged from 9.20 to 58.02 Bq m(-3) with a median of 34 Bq m(-3) and 7.21 to 59.27 Bq m(-3) with a median of 33 Bq m(-3), respectively. The arithmetic mean of progeny concentrations varies from 0.033 to 2.52 mWL with a median of 1.29 and 0.074 to 47.04 mWL with a median of 20.7, respectively. The dose to the selected population of Mysore city has been found to be 1.58, mSv y(-1). The concentrations of radon/thoron and their progeny vary with the type of flooring and ventilation conditions. Diurnal and seasonal variations have also been observed. Higher radon concentration has been found during nights and early morning hours.