Seasonal variation of indoor radon/thoron concentration of Budhakedar in Garhwal Himalaya, India

The main sources for indoor radon concentrations in all types of houses are the soil radon flux under the building (about 80%) and the radon exhalation from building materials (about 20%). Measurement of indoor radon, thoron and their daughter products were measured in the houses of the area for four different seasons (autumn, winter, summer and rainy) using LR-115 plastic track detectors. The detector is fixed in a twin chamber radon dosimeter, which can record the values of radon, thoron and their decay products separately. Detailed analysis of the effects of seasonal variation on radon, thoron and their decay products, inside the houses is given this paper. Radon concentration was found to be highest in winter and lowest in summer. Radon concentration in summer found to vary from 8 ± 1 to 79±5Bq/m³ with an average value 27±2Bq/m³, whereas in winter it varies from 10±2 to 137±7Bq/ m³ with an average value 55±4Bq/m³.The radon and progeny concentrations were found maximum in winter and minimum in summer. However, thoron values were found maximum in rainy and minimum in summer. (author)