Abstract
An indoor radon measurement survey has been carried out in the dwellings of Balakot city of North West Frontier Province of Pakistan using CR-39 based radon detectors. The main objective of this survey was to estimate radiation doses received by the dwellers of the Balakot city due to the indoor radon exposure. For this purpose CR-39 based radon detectors were installed in bedrooms and living rooms of 50 randomly selected houses. After 90 days of radon exposure, CR-39 detectors were etched for 9 h in 6 M NaOH at 70 degrees C and the observed track densities were related to radon concentrations. The measured indoor radon concentration ranged from 15 +/- 8 to 267 +/- 3 Bq m(-3) and 15 +/- 8 to 205 +/- 3 Bq m(-3) in bedrooms and living rooms, respectively. Weighted average radon concentration varied from 16 8 to 222 +/- 3 Bq m(-3). Based on the measured indoor radon data, the annual effective doses were found to vary from 0.30 +/- 0.20 to 5.60 +/- 0.08 mSv y(-1). The overall mean effective dose for the studied area was found to be 1.69 +/- 0.15 mSv y(-1).