Abstract
In this investigation, the activity levels of Indoor Radon-222, effective radium contents, exhalation rate of radon, and annual effective dose are reported for different indoor locations (Offices, Laboratories, Meeting rooms, and Storerooms) at two students divisions (boys, and girls) in science college, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia. Sealed-can technique based on CR-39 nuclear tracks detector was distributed to radon gas survey. The obtained results indicate normal levels of indoor radon concentration and effective radium content in all locations of the studied area. A strong correlation (R
2
=1) has been observed between effective radium content and radon exhalation rate. There is a slight increase in the values of exhalation rate at all locations. The average values of annual effective dose for boys division are 1.26, 1.51, 2.02, and 2.38 mSvy
−1
for meeting rooms, offices, storerooms, and laboratories, respectively. For girls division, the average values of annual effective dose are 0.86, 0.95, 1.53, 0.78 mSvy
−1
for meeting rooms, offices, storerooms, and laboratories, respectively.