Effects of Floor Levels and Ventilation Rate ...

Effects of floor levels (ground, first and second) and ventilation rate on the density of indoor radon and its progeny have been evaluated inside most of public hospitals. Ventilation rate is represented by the air moving rate; poor, fair, good, very good. Locations of the selected hospitals had different geological formation in three main governorates: Erbil, Duhok and Sulaymaniya. Nuclear track detector type CR-39 (CR-39NTDs) has been used to measure track density of alpha particles that emitted from radon and its progeny. During spring season, 72 pair of exposure chambers (open-close chamber) equipped with 144 pieces of CR-39NTDs installed inside 24 rooms for three floors were employed. After 90 day of exposure, exposed detectors were etched in 6N NaOH at 70◦C for 10 h. The highest and lowest radon concentration were in the hospitals of Shaheed Aso (Sulaymaniya city : 71.09±4.32 Bq.m-3)(fair ventilation) and Erbil Teaching ( Erbil city : 48.02±3.77Bq.m-3) (good ventilation). This was depended on the geological formation, type of building material, and the floor level. Therefore, the results showed that the average radon concentration and annual effective dose decreased gradually as the floor level increased. The highest and lowest of annual effective dose were found in ground and second floor, respectively. Thus, according to the annual exposure dose data, the workers were safety in most of the hospitals. More details about the type of building materials of the hospitals have been listed in full paper