Total outward leakage reduction efficiency of different protective masks using model viruses

Total outward leakage reduction efficiency against viral particles for masks is not well known. The objective of this study was to evaluate this efficiency for various masks against virus-containing polydisperse aerosols. To achieve that, a test bench previously built for particulate total outward leakage reduction efficiency evaluation was adapted to generate viral aerosols. Total outward leakage reduction efficiency against viral particles was measured for 10 different masks using a wind tunnel and a mannequin head. The impact of washing on the total outward leakage reduction efficiency was assessed for three barrier face coverings against viral particles. Total outward leakage reduction efficiency for viruses was generally higher than for particles (0.52–3.3 µm) since each of these particles could contain more than one virion and have a greater impact on the viral efficiency compared to particles. Washing did not have a major impact on the efficiency measured for the barrier face coverings tested. Total outward leakage reduction efficiency tests could be done using inert particles since total outward leakage reduction efficiency was lower against particles (0.52–3.3 µm) than against infectious viruses. However, using biological particles may be a better way to interpret the risk associated with infectious aerosols.