Indoor radon/thoron survey report from Hamirpur and Una districts, Himachal Pradesh, India.

A survey of indoor radon and thoron levels has been carried out in a number of villages in the vicinity of uranium bearing sites in the Hamirpur and Una districts of Himachal Pradesh (H.P.), India. Levels were analysed with reference to the nature of building material, soil type and different seasons of the year. The one year average for radon concentration was found to vary from a minimum of 19.7 to a maximum of 146.3 Bq/m3 while the minimum and maximum thoron concentrations were 9.1 and 70.7 Bq/m3, respectively. The dose rate varied from 0.1 to 8.67 microSv/h. These are discussed in the light of ICRP recommendations.