Assessment of annual effective dose due to outdoor radon activity in the environment of Bengaluru

Soil is the major source of radon to enter the living environment. In the present study, an effort was made to see the contribution of radon activity to the dose received by the public of the study region. The radon activity in soil gas and radon exhalation rate from the surface soil were measured in the Bangalore University campus using a continuous radon monitoring device called RAD7. The value obtained in the present investigation is ranged from 1690 ± 362 to 7390 ± 324 Bq/m³, with the geometric mean (GM) of 4120 ± 307 Bq/m³, and 13.97 ±7.55 - 24.82 ± 8.38 mBq/m²/s, with the GM of 18.13 ± 6.52 mBq/m²/s, respectively. The radon exhalation rate was also calculated using the values obtained from the radon activity in soil gas and is compared with the measured value. The annual effective dose (AED) was estimated from the measured radon concentration near to the soil surface and is found to be ranged from 0.02 to 0.07 mSv/y, with the GM of 0.04 mSv/y. The AED due to inhalation is well within the global average as reported in the UNSCEAR 2000, which indicates that there is no threat to the human due to the outdoor radon concentration in the study area. (author)