Environmental gamma dose rates and influencing factors in buildings

Environmental gamma radiation measured in buildings in Dhaka shows a cosinusoidal variation of indoor dose rate with time mainly due to seasonally varied ventilation and air exchange rates of the houses. In connection, the nature and characteristics of the buildings were also discussed. As expected, a maximum dose rate was found in winter and a minimum in summer. The variations of indoor dose rates between buildings were observed. This study indicates that the higher air exchange rates of the houses may play an important role in providing a healthy and safe indoor environment for their inhabitants by reducing indoor exposure.