MUHANNAD KH. MOHAMMED, MOHAMMED SH.NAJI, SALAM TAREQJAWAD, NABEEL HASHIM AMEEN AND HUDA NASSAR KARKOSH
Abstract
In this study, measurements of indoor and outdoor radon activity concentrations were carried out in the lecturer rooms, laboratories, corridors and gardens in the campus of the College of Basic Education/Al-Mustansiriyah University (Baghdad-Iraq) using solid state nuclear track detectors. 17 track detector type CN-85 were distributed inside building for measurement of indoor radon levels while 5 detectors were distributed outside buildings for measurements of outdoor radon levels during the period July-August 2017. The indoor radon activity concentrations ranged from 18.5 to 52 Bq/m3, with an average value of 36.52 ñ 8.35Bq/m3. In outdoor air spaces, radon activity concentrations ranged from 25 to 46Bq/m3, with an average value of 37.8 ñ 8Bq/m3. The variation of radon concentration with height of the floor is also discussed. The observed radon activity concentrations in the studied area were lower than the action level of 200 Bq/m3 recommended by the International Commission on Radiological Protection (ICRP). Dose rate and excess lifetime cancer risk were calculated. It was estimated that the College staff and students receive annual radiation dose of about 0.292mSv from composite indoor/outdoor radon gas and its short-lived daughters inhalation, which was considerably lower than the ICRP recommended action levels (3ââ¬â10 mSv/y). The results reported in this study imply an expected value for excess lifetime cancer risk probability of 0.058% due to inhalation of radon gas and its progeny.