indoor radon measurements in residential dwellings in qom, iran

background: inhalation of radon and its short-lived decay products is one of the ‎most significant sources of exposure to natural radiation. radon is the second cause ‎of lung cancer in the populations. the present study was carried out under the projects of ‎national radon, with the aim of determining the concentration of indoor in the city of qom ‎located in the central semi-arid region of iran.‎ materials and methods: radon measurements were carried out in 123 dwellings ‎using passive sampling with cr-39 detectors for 90 days. the map of radon ‎concentration distribution was prepared using arc gis software and the statistical ‎analysis was performed with spss version 20. results: indoor radon concentrations in qom dwellings ranged from 15–259 bq ‎m-‎‎3‎. the arithmetic mean of indoor radon concentrations on basement, ground floors, ‎first floors and second and upper floors were ‎123.43, 87.94, 63.72 and 40.69‎‏ ‏bq m-3, ‎respectively. conclusion: a correlation was found between the distances from fault zones and measured ‎indoor radon concentration. in most of cases, radon values were lower in well- ‎ventilated dwellings in comparison with poorly-ventilated ones. moreover, high radon ‎concentration levels were observed in basements. the results indicated that in 30 ‎places (24.3% of cases), the radon concentrations were higher than the reference levels ‎recommended by the world health organization (100 bq m-3).