The Covid-19 pandemic has led to an increasing awareness of the use of face masks and respirators in order to protect the wearer or the surrounding people against infections. Terms like FFP (filtering face piece), previously mainly known to experts, have become a part of the everyday language. The shortage of masks and the numerous initiatives for the production of DIY masks have given rise to a broad discussion about the suitability of materials to prevent the spreading of the disease. For people working in health and nursing care, the question about the maximal wear time of protection masks is of vital importance.
A Soaked Mask Has to Be Replaced – but How Long Does That Take?
A reliable protection does not only depend on the filtration properties of the mask material. It is known that moisture penetration decreases the filtering efficiency and therefore, the safety is reduced. Humidity and body heat enhance the microbial contamination on the wearer’s side of the mask. The most critical state is reached when the mask is imbrued entirely (moisture breakthrough), since the moisture can serve as an "infection bridge" spanning across the depth of the filter material. This holds for highly efficient filter masks (e.g. FFP-2), but even more so for masks to protect others: Coughing and sneezing can lead to the detachment of potentially infectious droplets from the outer surface which will then spread into the vicinity.