Comparison of indoor radon level with radon exhalation rate from soil in Garhwal Himalaya

The assessment of radiological risk related to inhalation of radon and radon progeny is based mainly on the integrated measurement of radon in both indoor and outdoor environments. The exhalation of radon from the earth crust and building materials forms the main source of radon in indoor environment. In this comparative study, the indoor radon level was measured using twin cup dosimeter in different dwellings of Garhwal Himalayas.Soil samples were collected simultaneously from different geological formations of the same area for laboratory measurement of radon exhalations rate. The radon exhalation rate was measured in the laboratory using LR-115 type II plastic track detectors. The indoor radon concentrations in this study area were found to vary from 13 ± 3 Bq/m3 to 178 ± 8 Bq/m3 with an average of 61 ± 5 Bq/m3 while thoron concentration was found to vary 9 ± 2 Bq/m3 to 94 ± 6 Bq/m3 with an average of 33 ± 3 Bq/m3. The radon exhalation rate was found to vary from (0.43 ± 0.05) × 10−5 Bq kg−1 h−1 to (20.10 ± 0.11) × 10−5 Bq kg−1 h−1 with an average of (1.95 ± 0.10) × 10−5 Bq kg−1 h−1. The detail significance of this study is discussed in radiation protection point of view.