en Radiation Biology Radiation Biology گزارش کوتاه Short Report <p></p> <p>Background: Inhalation of radon and its short-lived decay products is one of the <span dir="rtl">&lrm;</span>most significant sources of exposure to natural radiation. Radon is the second cause <span dir="rtl">&lrm;</span>of lung cancer in the populations. The present study was carried out under the projects of <span dir="rtl">&lrm;</span>national radon, with the aim of determining the concentration of indoor in the city of Qom <span dir="rtl">&lrm;</span>located in the central semi-arid region of Iran.<span dir="rtl">&lrm;</span> Materials and Methods: Radon measurements were carried out in 123 dwellings <span dir="rtl">&lrm;</span>using passive sampling with CR-39 detectors for 90 days. The map of radon <span dir="rtl">&lrm;</span>concentration distribution was prepared using Arc GIS software and the statistical <span dir="rtl">&lrm;</span>analysis was performed with SPSS version 20. Results: Indoor radon concentrations in Qom dwellings ranged from 15&ndash;259 Bq <span dir="rtl">&lrm;</span>m^-<span dir="rtl">^&lrm;&lrm;</span><span dir="rtl">³</span><span dir="rtl">&lrm;</span><span dir="rtl">.</span> The arithmetic mean of indoor radon concentrations on basement, ground floors, <span dir="rtl">&lrm;</span>first floors and second and upper floors were <span dir="rtl">&lrm;</span><span dir="rtl">123.43,</span><span dir="rtl"> 87.94, 63.72 </span>and 40.69<span dir="rtl">&lrm;&rlm; &rlm;</span>Bq m^-3, <span dir="rtl">&lrm;</span>respectively. Conclusion: A correlation was found between the distances from fault zones and measured <span dir="rtl">&lrm;</span>indoor radon concentration. In most of cases, radon values were lower in well- <span dir="rtl">&lrm;</span>ventilated dwellings in comparison with poorly-ventilated ones. Moreover, high radon <span dir="rtl">&lrm;</span>concentration levels were observed in basements. The results indicated that in 30 <span dir="rtl">&lrm;</span>places (24.3% of cases), the radon concentrations were higher than the reference levels <span dir="rtl">&lrm;</span>recommended by the World Health Organization (100 Bq m^-3).</p> <p></p> Keywords: Indoor radon, CR-39, dwelling, floor, fault. 331 339 http://ijrr.com/browse.php?a_code=A-10-1-636&slc_lang=en&sid=1 M. Fahiminia 790031947532846009991 790031947532846009991 No Research Center for Environmental Pollutants, Qom University of Medical Sciences, Qom, Iran R. Fouladi Fard 790031947532846009992 790031947532846009992 No Research Center for Environmental Pollutants, Qom University of Medical Sciences, Qom, Iran R. Ardani 790031947532846009993 790031947532846009993 No Research Center for Environmental Pollutants, Qom University of Medical Sciences, Qom, Iran A. Mohammadbeigi 790031947532846009994 790031947532846009994 No Research Center for Environmental Pollutants, Qom University of Medical Sciences, Qom, Iran K. Naddafi 790031947532846009995 790031947532846009995 Yes Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran M.S. Hassanvand 790031947532846009996 790031947532846009996 No Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran