Evaluation of commercial facemasks to reduce the radioactive dose of radon daughters

Commercial facemasks have become a common tool during the COVID-19 pandemic. They are cheap, simple to use and some are capable of filtering out most particles in the air, protecting the user. These qualities are usually employed in relation to hurtful viruses or contaminants, but they could also be used to prevent the radioactive dose due to radon, which is the second leading cause of lung cancer worldwide. For that reason, the main goal of this study is to verify if facemasks could prevent radon decay products from entering the potential user’s lungs. Since these decay products are the main source of radioactive dose, several commercial facemasks were tested by exposing them to radon and then measuring the presence of radon daughters by gamma spectroscopy. Reusable facemasks made from materials such as cotton, polyester or neoprene appeared to be inefficient with only 40% filtering efficiency, Polypropylene woven masks being the only exception, with 80% efficiency. Surgical masks presented filtering efficiencies between 90 and 98%. FFP3 and FFP2 proved to be the most reliable, almost completely filtering out radon daughters with filtering efficiencies up to 98%. Results prove that the use of FFP3 and FFP2 facemasks could be a useful tool to reduce the radioactive dose due to radon in places where other techniques cannot be used or are not advisable.