• Ogungbemi, I. Kayode
  Department of Physics, University of Lagos, Akoka -Yaba, Lagos, Nigeria
  




• Olopade, A. Muteeu
  Department of Physics, University of Lagos, Akoka -Yaba, Lagos, Nigeria
  




• Oyebola O.Olusola
  Department of Physics, University of Lagos, Akoka -Yaba, Lagos, Nigeria
  

Radon activities in the offices have been reported on five different floors to ascertain annual equivalent dose (AEqD) and excess lifetime cancer risk due to gamma radiations for a period of six months. RAD7, an electronic radon detector manufactured by Durridge Co. USA calibrated in-house was used to measure the indoor radon concentration levels in offices of the Administration block. Mean radon concentration from offices studied ranged from134.72 Bqm-3 - 536.98 Bqm-3 in all the offices. The mean of the annual effective dose due to 222Rn progeny (AEDR) in mSv/yr. is highest in GFL. This value is 2.344 x 10-3 mSv/yr. and it’s lowest at the LFL with the value of 1.010 x 10-3 mSv/yr. The lung cancer cases mean, maximum and the 95th percentile per million people values obtained from offices and the obtained values are 85.81, 11.44, and 11.21. The obtained values were lower than the public limit of 1 mSvy-1 as recommended by ICRP, and these findings show a significant correlation between indoor radon effective doses obtained by other studies elsewhere.