Radon in Soil Gas and Ambient Dose Equivalent Rate Measurements in Yaoundé, Cameroon

Abstract

This study measured radon (²²²Rn) concentrations in soil gas and ambient dose equivalent rates in various neighborhoods of Yaoundé, Cameroon. MARKUS 10 detector was used to measure radon in soil gas at 50 cm of depth. The ambient dose equivalent rate measurements were performed at the height of 1 m above ground, using a pocket survey meter (RadEye PRD-ER, Thermo Scientific). The results obtained from the radon concentration in soil gas measurements ranged from 8.4 to 50.7 kBq m^-3 with a geometric mean of 25.4 kBq m^-3. Ambient dose equivalent rates ranged from 0.02 to 0.11 µSv h^-1 with an average value of 0.05 µSv h^-1. These measurements were followed by calculating radon surface exhalation rates, and the annual outdoor external effective dose. Radon surface exhalation rates ranged from 41.5 to 250.5 mBq m^-2 s^-1 with an average value of 139.8 mBq m^-2 s^-1. The annual outdoor external effective dose varied between 0.07 and 0.39 mSv with an average value of 0.17 mSv. The correlation between radon concentration in soil gas and ambient dose equivalent rates was analyzed. A Pearson correlation coefficient r = 0.81 was obtained, indicating the strong correlation between them, and one can serve as the indicator of the other.