Published online by Cambridge University Press: 17 December 2010
The sedimentary sandstone and clay sequence of the Miocene Kamlial and Murree Formationsis exposed in the sub-Himalayas of the Dhirkot area, State of Azad Jammu and Kashmir,Pakistan. The indoor radon and outdoor gamma dose rates were measured from dwellings andbasement sandstone and clay rocks, respectively. The radon concentration in dwellings was36 ± 14 Bq.m-3 to 195 ± 27 Bq.m-3, with an average of 121 ± 26Bq.m-3. The average radon concentration in pucka, semi-kucha and kucha houseswas 124 ± 25 Bq.m-3, 143 ± 25 Bq.m-3 and 136 ± 26Bq.m-3, respectively. The outdoor gamma dose rates for the basementsandstones and clays of the Murree Formation and Kamlial Formation were 74.0 ± 1.4–113.1± 2.4 nGy/h and 69.6 ± 2.2–108.8 ± 1.4 nGy/h, respectively. The average gamma doserates for the Murree and Kamlial Formations were 91.3 ± 14.3 nGy/h. The gamma dose rateis maximum (113.1 ± 2.4 nGy/h) and minimum (69.6 ± 2.2 nGy/h) at higher (5 539 feet)and lower (4 493 feet) altitudes, respectively. The overall causes for the increase inaverage radon concentration in dwellings of the Dhirkot area were poor ventilation, oldhouses, humidity and temperature, cracks in houses, geology, and aggregates. The gammadose rate variation depends on sandstone and clay lithologies, altitude and radionuclidecontributions. This study shows that the average radon (121 ± 26 Bq.m-3)concentration for the inhabitants of the Dhirkot area was within the accepted safe healthlimit (200 Bq.m-3, ICRP, 1993; UNSCEAR, 1993).