Indoor Radon Concentrations and Assessment of Doses in Four Districts of the Punjab Province - Pakistan

摘要

Seasonal indoor radon measurement studies have been carried Out in four districts, namely, Jhelum, Chakwal, Rawalpindi and Attock of the Punjab Province. In this regard, CR-39 based detectors were installed in bedrooms, drawing rooms and kitchens of 40 randomly selected houses in each district. After exposing to radon in each season, CR-39 detectors were etched in 6M NaOH at 80 degrees C and counted Under all optical microscope. Indoor radon activity concentrations in the houses Surveyed ranged from 15 +/- 4 to 176 +/- 7 Bq m(-3) with an overall average value of 55 +/- 31 Bq m(-3). The observed annual average values are greater than the world average of 40 Bq m(-3). Maximum, indoor radon concentration levels were observed in winter season whereas minimum levels were observed in Summer season. None of the measured radon concentration value exceeded the action level of 200-400 Bq m(-3). The season/annual ratios for different type of dwellings varied from 0.87 +/- 0.93 to 1.14 +/- 1.10. The mean annual estimated effective dose received by the residents of the studied area was found to be 1.39 +/- 0.78 mSv. The annual estimated effective dose is less than the recommended action level (3-10 mSv).