Measurement of Radon Concentration in Selected Houses in Ibadan, Nigeria

Radon is a natural radioactive gas without colour or odour and tasteless. The World Health Organization (WHO) grouped radon as a human lung carcinogen. For this reason, there has been a lot of interest on the effects of radon exposure to people all over the world and Nigeria is no exception. The aim of this study is to investigate the radon concentration in selected houses in three local government areas of Ibadan. The indoor radon was measured in both mud and brick houses. Fifty houses were considered from the three Local government areas. A calibrated portable continuous radon monitor type (RAD7) manufactured by Durridge company was used for the measurement. A distance of 100 to 200 m was maintained between houses in all the locations. The living room was kept closed during the measurements. The mean radon concentration measured in Egbeda is 10.54 +/- 1.30 Bqm(-3); Lagelu is 16.90 +/- 6.31 Bqm(-3) and Ona-Ara is 17.95 +/- 1.72 Bqm(-3). The mean value of the annual absorbed dose and annual effective dose for the locations in the three local government areas was 0.19 mSvy(-1)and 0.48 mSvy(-1)respectively. The radon concentration for location 10 in Ono-Ara local government exceeded the recommended limit. However, the overall average indoor radon concentration of the three local governments was found to be lower than the world average value of 40 Bqm(-3). Hence, there is need for proper awareness about the danger of radon accumulation in dwelling places.