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Indoor radon and its decay products are considered to be the second leading cause of lung cancer after cigarette smoking. This is why extensive radon surveys have been carried out in many countries of the world, including Pakistan. In this context, 25 spots were selected at workplaces in the vicinity of the uranium mining site in Dera Ghazi Khan District for indoor radon measurement. For this purpose, CR-39 based radon detectors were installed at head height and were exposed to indoor radon for 60 days. After retrieval, these detectors were etched in a 6 M solution of NaOH at the temperature of 80 C for 16 h in order to make the alpha particle tracks visible. The observed track densities were related to the indoor radon concentration using a calibration factor of 2.7 tracks cm-2 h-1=kBq m-3. The measured indoor radon concentration ranged from ~386 ±161 to 3028 ± 57 Bq m-3 with an average value of 1508 ± 81 Bq m-3 in the studied areas of Dera Ghazi Khan District. The mean annual effective dose ranged from 2.22 ± 0.93 to 17.44 ± 0.33 mSv yr-1, with an average of 8.68 ± 0.47 mSv yr-1. The effect of the seasonal correction factor (SCF) on the annual average radon concentration has also been considered. Results of the current study show that, for the majority of the workplaces studied, indoor radon levels exceed the action levels proposed by many world organisations. [ABSTRACT FROM AUTHOR]

In continuation to our earlier studies concerning generation of the baseline indoor radon data, an indoor radon measurement survey was carried out in the districts Bagh and Kahuta, state of the Azad Jammu and Kashmir. In this context, 150 houses were selected in the aforesaid districts and CN-85-based box-type radon detectors installed in bedroom and living room of each house. The detectors were exposed to indoor radon for 3 months. After etching CN-85 detectors in 6 M NaOH at 70°C for 3 h, the observed track densities were related to the indoor radon concentration using calibration factor of 0.0092 tracks cm−2·h−1 per Bq·m−3. The measured indoor radon concentration ranged from 56 to 124 Bq·m−3 and 61 to 106 Bq·m−3 in the studied areas of districts Bagh and Kahuta, respectively. The mean annual effective dose ranged from 1.42 ± 0.15 to 3.12 ± 0.10 mSv·y−1 with an average of 2.16 ± 0.13 mSv·y−1 in the district Bagh and 1.54 ± 0.14 to 2.68 ± 0.12 mSv·y−1 with an average of 2.17 ± 0.13 mSv·y−1 in the district Kahuta. These values are within the safe limits recommended by the World Heath Organization. [ABSTRACT FROM AUTHOR]