Indoor and outdoor radon levels and its diurnal variations in Botswana

Studies on radon monitoring are essential for countries actively involved in mining activities. Since large-scale mining activities have the potential to enhance the background radiation levels, a detailed study on indoor and outdoor radon levels, its diurnal variation with temperature, pressure and humidity for Botswana is initiated. The study is important because such studies for Botswana are non-existent and the database on indoor and outdoor 222Rn concentration and the resulting inhalation dose to the population of the region is not available. Measurements were carried out using the AlphaGuard (Genitron,Germany) Professional Radon Monitor. The concentration of 226Ra in soil was also measured by gamma spectrometry using a 41% relative efficiency n-type HPGe detector (Canberra, USA). Initial results show that the indoor 222Rn concentration vary in the range 3.0–93.0 Bq m−3 with a mean of 24.5 Bq m−3. Diurnal variation studies show that the concentration is higher in the early morning hours and lower in the early afternoon hours. All the results are presented and discussed in detail in this paper.