Estimation of background radiation in the indoor air in geo-sensitive zones of the Garhwal Himalaya, India

The study assesses environmental background radiation from radon, thoron, and thoron decay products across distinct geological settings in the Garhwal Himalaya region by using RADUET, CR-39 plastic track detectors, and deposition-based thoron ( 220 Rn)progeny detectors. The measurements were conducted indoors throughout the winter, summer, and rainfall seasons during the year 2013. The annual inhalation doses from 220 Rn progenies ranged between 0.83 and 2.99 mSv y −1 , averaging 1.94 mSv y −1 . The annual effective dose (AED), reflecting biological radiation impact, varied from 0.58 to 2.78 mSv y −1 , with an average of 1.75 mSv y −1 .