Measurements of indoor radon concentration levels in dwellings in Bethlehem, Palestine.

Indoor radon level measurements were carried out in 42 dwellings in Bethlehem, Palestine, using CR-39 solid state nuclear track detectors. The measurements were performed during winter and spring seasons of the year 2010, for a period ranging from 97-118 d using a total of 100 detectors. The detectors were installed in living rooms, bedrooms, kitchens, and storage areas of 39 houses, as well as in three schools, selected randomly in the surveyed area. The results of indoor radon levels and the annual effective dose in houses were found to vary from 26 - 611 Bq m(-3) and 0.65 - 14.1 m Sv y(-1), with average values of 117.0 Bq m(-3) and 2.95 m Sv y(-1), respectively. The mean values of radon concentration levels in bedrooms, kitchens, living rooms, basements, and storage areas are, respectively, 106.5, 113.1, 101.5, and 164.2 Bq m(-3). The corresponding mean values of annual effective dose for the bedrooms, kitchens, living rooms, basements, and storage areas are 2.66, 2.83, 2.54, 14.1 m Sv y(-1), respectively. In schools, the radon levels are found to vary from 31 - 400 Bq m(-3) with an average value of 125.1 Bq m(-3). The average annual effective dose in schools is found to be 3.12 mSv y(-1). This value is higher than the assigned international value. In general, the results show that radon concentration levels in 83% of the investigated dwellings are lower than the indoor radon action level of 150 Bq m(-3) for the United States.