Radiometric investigation of indoor environments: assessment of radon and gamma radiation exposure in residences of a tropical metropolitan city in Brazil

This study evaluated indoor exposure to radon-222 and gamma radiation in Belo Horizonte, Brazil, aiming to characterize natural radiation levels in residential environments. Radon concentrations showed spatial variability and a pronounced seasonal variation, highlighting the influence of climatic and ventilation conditions on radon accumulation, with some residences exceeding recommended reference levels. The integrated assessment of radon and external gamma radiation indicated annual exposure values comparable to global natural radiation levels. The findings highlight the influence of local environmental conditions and the importance of systematic monitoring to support radiological protection strategies in Brazil.