Assessment of indoor radon concentration in the dwellings of the industrial areas of Kannur District, Kerala.

All organisms on the earth-crest are exposed to natural background radiation since the evolution of the earth, as many environmental matrices such as soil, air, water bodies, vegetation, etc., act as the sources of natural radioactivity. The present study deals with the evaluation of indoor concentration of 222Rn (radon) in different dwellings with various construction materials used for the roof and floor in the industrial sites of Kannur district, Kerala. A pinhole-based dosemeter coupled with LR-115 Solid State Nuclear Track Detector and Direct Radon Progeny Sensor (DRPS) were respectively used for the measurement of indoor radon concentration and equilibrium equivalent concentration of radon. The indoor radon concentrations were found to vary from 102.30 Bqm-3 to 184.75 Bqm-3 and the values were within the recommended limits provided by International Commission on Radiological Protection (ICRP). The annual effective doses and excess lifetime cancer risks were observed in the range of 2.58-4.66 mSvy-1 and 7.68 × 10-3-15.60 × 10-3, respectively, and both exceed the world average values recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2000. The study shows that, the houses with marble floors and concrete roofs have comparatively higher values of radon concentration, which indicates the significant contribution of construction materials to the enhanced radiation levels inside the dwellings.