Asian Journal of Physical and Chemical Sciences

Measurement of indoor and outdoor radon concentration in five different types of residential buildings were done using two Corentium Radon detector of model type; BQM-Digital Radon detector. It was done simultaneously and the readings taken after 24 hours for five days in a particular residential building. The average indoor radon concentration measured   varies from 2.15± 3.14 to 29.60±0.76 Bqm^-3 respectively while the average outdoor radon concentration levels measured for five days in five different residential buildings range from 0.96±0.50 to 10.80±5.87 Bqm^-3. The progeny of indoor radon varied from 0.2 x 10^-3 WL to 3.2 x 10^-3 WL while that for outdoor varied from 0.20x 10^-3 to 1.8 x 10^-3 WL. The mean indoor concentration of radon was considered less than the prescribed lower levels of 100 Bqm^-3.  The annual effective dose to lungs (H_EL) and whole body (H_EW) calculated from the indoor radon concentration varied from 0.384 to 5.24 mSvy^-1 and 0.13 to 1.79 mSvy^-1 respectively.  Annual effective dose to the lungs and whole body are relatively within the recommended lower limit of 1.0 mSvy^-1. Though the unplastered block house and mud house recorded relatively high radon concentration and other health risk parameters, the occupants of all the studied buildings are safe, since there will be no immediate health risk but prolonged stay might be detrimental to their health. The paper therefore recommended safety tips that will help reduce radon concentration in such houses.