Seasonal Variations and Dose Estimation of Indoor Radon ( ²²² Rn), Thoron ( ²²⁰ Rn), and Their Progenies in Malwa Region, Punjab, India

ABSTRACT A comprehensive investigation was conducted to evaluate the levels of radon ( 222 Rn), thoron ( 220 Rn), and their offspring in the interior habitats of Moga District, Punjab, India. SSNTD‐based progeny sensors (DRPS/DTPS) and single‐entry pinhole dosimeters following the standard approach advised by BARC, Mumbai, India, were used. The measured annual average 222 Rn level ranged from 16 to 65 Bq m −3 with an average of 33 ± 4 Bq m −3 , which was found well below the recommended level of 300 Bq m −3 . Annual 220 Rn concentration varied from 17 to 114 Bq m −3 , with an average of 47 ± 12 Bq m −3 exceeding 10 Bq m −3 (worldwide thoron average) suggested by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Seasonal variation was observed as rainy > winter > summer. The 222 Rn progeny annual average level (EERC) falls short of the UNSCEAR‐recommended global threshold of 15 Bq m −3 , with values ranging from 7 ± 0.8 to 22 ± 1.5 Bq m −3 and a mean of 12 ± 1.0 Bq m −3 . The 220 Rn progeny yearly average concentration (EETC) is higher than the UNSCEAR‐recommended worldwide value of 0.5 Bq m −3 , ranging from 0.39 ± 0.06 to 2.45 ± 0.14 Bq m −3 with a 0.88 ± 0.09 Bq m −3 mean value. The average yearly effective dose was 0.94 mSv year −1 , well within the International Commission on Radiological Protection (ICRP)‐recommended safety limits of 14 mSv year −1 for houses. The results highlight the necessity of ongoing surveillance and preventative measures to guarantee indoor air quality and protect public health.