The effect of floor level on radon concentration in ventilated rooms

Radon is colourless and odourless radioactive gas produced naturally in rocks, soils building materials. There is a strong correlation between radon exposure and lung cancer. Therefore, high levels of radon concentrations such as in buildings should be avoided. In this study, the investigation of indoor radon concentration in rooms in selected student hostel buildings at Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia without air conditioning system was conducted. The indoor Radon concentration were detected using Solid State Nuclear Track Detector (SSNTD) CR-39, which is put in a constructed radon monitor. A total of 28 monitors were placed in rooms in five four-story buildings and one eight-story building. These radon monitors were left for a month before undergoing etching process with NaOH (6 N) solution at 70°C for six hours. The radon concentrations were determined from the track density in each CR-19 sampling. From the analysis, the radon concentrations were between 2.17–0.25 Bq/m3 and 6.72–0.77 Bq/m3 and the average was 4.42 Bq/m3. No significant relationship between radon concentration and floor level observed due to very low radon concentration value as a result of good ventilation. All annual effective dose were lower than the global limit indicating that the rooms were radiologically safe.