Measurement of indoor radon and thoron in the dwellings of Faizabad city using plastic track detectors

LR-115 type II plastic track detectors have been used to measure the concentration of radon, thoron and their progeny (in winter season) inside the dwellings of Faizabad city of UP, India. The values of radon and thoron concentration have been found to vary fromll.57 to 104.10 Bq/m(3) and 5.78 to 43.74 Bq/m(3) with an average value of 60.57 Bq/m(3) and 26.12 Bq/m(3), respectively. The inhalation dose due to radon, thoron and their progeny was found to vary from 0.45 to 3.55 mSv/y with an average value of 2.21 mSv/y. The average value of radon and thoron daughter's concentration (i.e. potential alpha energy concentration, PAEC) was found to be 6.54 mWL (milli-working level) and 0.70 mWL, respectively. The annual exposure from radon and thoron daughters collectively has been varied from 0.057 to 0.502 WLM (working level month) and the values of life time fatality risk have been found to vary from 0.17x10(-4) to 1.51x10(-4) with an average value of 0.30 WLM and 0.89x10(-4), respectively. However, the values of annual effective dose from radon and thoron daughters vary from 0.22 to 1.93 mSv/y with an average value of 1.15 mSv/y. All the values in the above study have been found under the safe limit laid down by International Commission on Radiological Protection (ICRP) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).