Indoor radon measurements in residential dwellings in Qom, Iran

Inhalation of radon and its short-lived decay products is one of the ýmost significant sources of exposure to natural radiation. Radon is the second cause ýof lung cancer in the populations. The present study was carried out under the projects of ýnational radon, with the aim of determining the concentration of indoor in the city of Qom ýlocated in the central semi-arid region of Iran.ý
Radon measurements were carried out in 123 dwellings ýusing passive sampling with CR-39 detectors for 90 days. The map of radon ýconcentration distribution was prepared using Arc GIS software and the statistical ýanalysis was performed with SPSS version 20.
Indoor radon concentrations in Qom dwellings ranged from 15–259 Bq ým-ýý3ý. The arithmetic mean of indoor radon concentrations on basement, ground floors, ýfirst floors and second and upper floors were ý123.43, 87.94, 63.72 and 40.69ýþ þBq m-3, ýrespectively.
A correlation was found between the distances from fault zones and measured ýindoor radon concentration. In most of cases, radon values were lower in well- ýventilated dwellings in comparison with poorly-ventilated ones. Moreover, high radon ýconcentration levels were observed in basements. The results indicated that in 30 ýplaces (24.3% of cases), the radon concentrations were higher than the reference levels ýrecommended by the World Health Organization (100 Bq m-3).