Role of consolidants for limiting the radon exhalation rate in building materials of historical and artistic interest

This study evaluates the effectiveness of consolidants in reducing radon (Rn-222) exhalation from building materials commonly found in historical structures. Radon, a radioactive gas derived from Ra-226 decay, represents a significant indoor health risk due to its tendency to accumulate. Experimental investigations were conducted within the ATHENA project, assessing radon emission from various lithotypes subjected to accelerated aging and treated with different consolidants, including PDMS, NanoEstel (silica-based materials), and NanoRestore (calcium-based material). Radon exhalation rates were measured using a closed chamber method connected to a RAD7 detector, focusing particularly on Viterbo tuff. Results demonstrated an exponential increase in radon levels before reaching equilibrium, highlighting significant variations based on material composition, porosity, and applied consolidants. Notably, NanoEstel showed a remarkable reduction in radon emissions compared to untreated and other consolidant-treated samples. These findings underscore the importance of consolidants in heritage conservation, emphasizing their potential role in improving indoor air quality and safeguarding public health. This research was carried out as part of the PRIN 2022 PNRR ATHENA project, funded by the European Union through the Next Generation EU initiative.