Measurement of indoor radon, thoron and their progeny levels in dwellings of Union Territory Chandigarh, India: correlation with radon exhalation rates. Issue 6 (October 2015) - Mehta, V.
Presence of radon, thoron and their decay products in household environment is considered a potential health hazard. Measurement of their levels is an important aspect to assess the threat they may pose to humans. Considering this their measurement from some dwellings of Union Territory Chandigarh, India has been carried out. Seasonal variation of these values has also been studied. A correlation study of exhalation rates from soil samples of areas close to the dwellings has also been carried out. The indoor radon concentration varied from 7.9 ± 0.5 to 39.2 ± 2.3 Bq m −3 with an average of 23.3 Bq m −3 while the thoron concentration in the same dwellings varied from 0.15 ± 0.01 to 24.6 ± 1.0 Bq m −3 with an average of 10.7 Bq m −3 . Annual effective dose varied from 0.3 to 1.4 mSv with an average of 0.8 mSv. The radon mass and surface exhalation rates from the soil samples varied from 0.9 to 1.9 mBq/kg/h with an average of 1.39 ± 0.29 mBq/kg/h and 20.7–42.3 mBq/m 2 /h with an average of 31.4 ± 6.8 mBq/m 2 /h, respectively. The value of in situ gamma dose found to be varied from 0.14 to 0.31 µSv/h.