Indoor radon measurements in residential dwellings in Qom, Iran

Background: Inhala on of radon and its short-lived decay products is one of the most significant sources of exposure to natural radia on. Radon is the second cause of lung cancer in the popula ons. The present study was carried out under the projects of na onal radon, with the aim of determining the concentra on 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 concentra on distribu on was prepared using Arc GIS so+ware and the sta s cal analysis was performed with SPSS version 20. Results: Indoor radon concentra ons in Qom dwellings ranged from 15–259 Bq m . 3 The arithme c mean of indoor radon concentra ons on basement, ground floors, first floors and second and upper floors were 123.43 , 87.94 , 63.72and 40.69 Bq m -3 , respec vely. Conclusion: A correla on was found between the distances from fault zones and measured indoor radon concentra on. In most of cases, radon values were lower in wellven lated dwellings in comparison with poorly-ven lated ones. Moreover, high radon concentra on levels were observed in basements. The results indicated that in 30 places (24.3% of cases), the radon concentra ons were higher than the reference levels recommended by the World Health Organiza on