On the relation of geology, natural ventilation and indoor radon concentration: the northern Portugal case study

• Autor(a) principal: Curado, António
• Data de Publicação: 2021
• Outros Autores: I. Lopes, Sérgio, Antão, Ana Maria Morais Caldas
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.9/3567
• topic: Radon; Granitic soil; Ventilation; Occupancy; Indoor air quality; Radão; Solo granítico; Ventilação; Ocupação; Qualidade do ar interior

Alto Minho region, Northwest of Portugal, presents high indoor radon concentrations due to the granitic nature of the soil. Indoor radon concentration is related to the amount of uranium and radium in the building foundation soil. According to the World Health Organization, it is proved that radon exposure in poorly ventilated buildings enhances lung cancer risk. An assessment campaign in a set of granitic buildings in the Alto Minho region, based on short-term measurements, was carried out with a specific focus on the influence of occupancy and ventilation actions performed by residents on the variation of radon concentration, indoor air temperature, and relative humidity. Results attained show to exist an influence of the air renovation on the reduction of radon concentration, therefore, buildings with low occupancy and reduced ventilation present higher indoor radon concentration and poor thermal comfort conditions. 67% of the evaluated buildings show radon concentrations below the reference value of 300 Bq.m−3 suggested by Portuguese regulation, highlighting the importance of human occupancy – mostly through passive ventilation processes – as a radon concentration mitigation factor. On the other hand, buildings sporadically occupied and, therefore, badly ventilated show higher indoor radon concentrations. Likewise, building where occupants reveal to have a lack of ventilation routine, present also high indoor radon concentrations.