Measurements of 222Rn, 220Rn and their progeny concentrations indoors around a coal/gas-based power plant and estimation of annual inhalation dose to the public

In the present study, indoor radon (222Rn), thoron (220Rn), radon progeny (214Po) and thoron progeny (212Po) activity concentration have been measured in a region around the National Capital Power Station, Dadri, Uttar Pradesh, India. The mean values of the 222Rn, 220Rn and their progeny in the studied region are found to be 22.1 ± 10.0 Bqm−3, 48.6 ± 13.5 Bqm−3, 8.8 ± 4.8 Bqm−3 and 0.49 ± 0.15Bqm−3 respectively. The annual inhalation dose estimated from the observed concentrations varies from 0.29 ± 0.04 to 2.06 ± 0.121 mSv with a mean value of 0.75 ± 0.32 mSv and is well within the reference level. It has also been observed that 212Po is a significant contributor (= 18.7%) to the total annual inhalation dose. Seasonal variations of 222Rn, 220Rn, and their progeny have also been reported.