Estimation of Indoor Radon Levels in Cities of Rajasthan by SSNTD

Indoor radon levels in dwellings in about a dozen cities of Rajasthan have been estimated using LR-115 type II peelable films. These films, fitted in the bottom of aluminium cups of 65 mm diameter and 35 mm height, were exposed for periods of 30-45 days. The houses are built of red sandstone and are well ventilated. The minimum and maximum values of radon activity were 12 and 190 Bq.m −3 . The corresponding annual effective dose equivalents have also been computed.