Measurement of indoor radon concentration levels in Islamabad, Pakistan

Indoor radon measurement survey has been carried out in properly selected houses of the city of Islamabad. In this regard, CR-39-based NRPB radon dosimeters were used. The dosimeters were installed at head heights in bedroom and living room of each house. For intercomparison purpose, houses having basements were also selected. In such houses, dosimeters were installed in basements, ground floor and first floor. All the dosimeters were exposed to radon for a period of three months. After exposure, CR-39 detectors were etched for 16 h in 6 M NaOH at 80∘C and were counted under an optical microscope. The observed track densities were then related to radon concentration levels using a calibration factor of 2.7trackscm-2h-1(kBqm-3)-1. Measured indoor radon concentration levels were found to vary from 11 to 78Bqm-3. The average radon concentration levels in bedrooms and sitting/living rooms in basements were found to be 40 and 32Bqm-3, respectively. In bedrooms and living rooms, on ground floor, the average radon concentration levels were found to be 30 and 27Bqm-3, whereas on first floor the average values were 29 and 27Bqm-3, respectively. The radon concentration levels found in this study are below the action level recommended by the ICRP.