Inner wall filler as a singular and significant source of indoor radon pollution in heritage buildings: An exhalation method-based approach

A significant source of indoor radon pollution in heritage buildings, such as the Tower of Hercules in Corunna, Spain, has been identified: inner wall fillers used in thick structural elements like bearing walls and vaults. These fillers exhibit radon exhalation rates comparable to those found in soils, often one to two orders of magnitude higher than the construction materials themselves (e.g., granite). The study employed an exhalation method-based approach, revealing that these fillers contribute substantially to indoor radon concentrations uniformly across building storeys, regardless of elevation or distance from the soil. This challenges conventional assumptions that soil is the primary source of radon gas and suggests that mitigation strategies must address emissions from all sources, including inner wall fillers.

Frutos, B., Martín-Consuegra, F., Alonso, C., Perez, G., Peón, J., Ruano-Ravina, A., Barros, J. M., & Santorun, A. M. (2021). Inner wall filler as a singular and significant source of indoor radon pollution in heritage buildings: An exhalation method-based approach. Building and Environment, 201, 108005. https://doi.org/10.1016/j.buildenv.2021.108005