Evaluation of the Outward Protection Efficacy of Masks and Respirators Against Viral Aerosols

This study evaluated the outward protection performance of various masks and respirators against viral aerosol emission, considering factors like wearing style, sampling point, and breathing condition. Using a headform with cyclic breathing, we tested four variables: device type, wearing style, sampling point, and breathing situation. A split-plot design with 126 experiments was employed, and Fisher's LSD analysis ensured reliable data. Results showed significant differences in Total Outward Leakage (TOL) among devices, with the cup mask offering the best protection and FFP3 NR-valve the worst. Improper wearing styles, especially "pulled-down-to-nose-clip," increased TOL by 1.3 to 3 times. Sampling points and respiratory changes also affected TOL, with the nose clip area recording the highest leakage. The study highlights the importance of proper mask usage and device selection for effective outward protection.