Measurement of Radon Concentration in Selected Buildings in Nnamdi Azikiwe University, Awka

Abstract

Radiation due to Radon gas and its progeny constitutes 50% of the total background radiation exposure. The odourless, colourless and tasteless property of the gas makes it difficult to detect its presence. It can only be detected when measured using a detector. The radioactive decay of radon has a deterministic effect on human lungs when inhaled. For this reason, the World Health Organization (WHO) grouped radon as a human lung carcinogen. The aim of this study was to estimate the average radon concentration in Nnamdi Azikiwe University. Radon levels were measured in eleven different buildings on the campus using the RD 200 radon-eye detector.  The indoor radon concentration was measured in both ground floors and upstairs. The average radon concentration measured on the ground floor was 55.03 ± 9.51 Bq.m-3 and 13.90 ± 3.83 Bq.m-3 on the upper floor. The implication of this result is that a person that spends a total of 2000 hrs/yr in these ground floor locations will be exposed to an average effective dose of 0.38 mSv.y-1, while a worker that spends equal time in the upstairs locations will accumulate an average of 0.096 mSv.y-1. Generally, the mean radon concentration in the campus was measured to be 36.34 Bq.m-3 which is a bit lower than the global average of 40 Bq.m-3. The mean annual effective dose for this study was found to be 0.25 mSv.y-1 which is lower than the recommended limit of 1 mSv.y-1. The data from this research offers a reference point for designing the ventilation system of future buildings in the school.