Determination of radon activity concentrations at closed stations of Izmir metro

Radon which is a product of Uranium decay series is a colorless, odorless and radioactive inert gas. Besides, Radon is thought that it is one of the serious reasons of the lung cancer in worldwide. For this reason, it is significant that radioactivity contribution that stems from radon should be determined for indoor areas such as houses, offices, mines, caves and tunnels. However, the level of human exposure to radioactivity has not been studied yet in metro stations which are used intensely for transportation in İzmir. So, within this thesis study, it was aimed to determine the radon activity concentrations at full-closed stations named as Evka-3, Ege Üniversitesi, Basmane, Çankaya, Konak, Üçyol, İzmirspor, Hatay, Göztepe, Poligon ve Fahrettin Altay in İzmir Metro (İzmir urban public transportation). LR-115 nuclear track or nuclear film detectors were hanged on suitable parts of the stations 50 cm above the rails and have been changed with new ones every month periodically for a year. As a result of this study, annual and monthly radon activity concentrations were calculated at closed stations. In addition, annual effective dose equivalent values were calculated for workers worked on the platforms of these stations for eight hours and for passengers waited for ten minutes. Obtained data was compared to previous local and international reference values. As a consequence of this study, the lowest mean for annual radon activity concentrations was calculated as 249.03 Bqm-3 at Konak Station and the highest mean value was 723.69 Bqm-3 at Üçyol Station. The mean of the radon concentrations calculated at all over the stations was found 392.86 Bqm-3. All these values were under the reference values determined by TAEK (2000). Average of the annual effective dose equivalent for workers working approximately 8 hours a day at the platforms was calculated as 4.13 mSvy-1 while maximum was 7.61 mSvy-1 (at Üçyol Station) and minimum was 4.13 mSvy-1 (at Konak Station). On the other hand, the average annual effective dose equivalent for passengers waited for approximately 10 minutes was 0.086 mSvy-1. All these values were under the reference values determined by ICRP (2007).