Surgical or procedural masks intended to prevent large particles expelled by the wearer into the environment are thin, multi-layer fabric masks. The outer layer is generally fluid resistant to mitigate the penetration of bodily fluids (by splash or droplet). The middle layer is a filtration pad that serves to prevent the passage of droplets and particulates, and a third layer lies against the face, mouth and nose. The three layers are sealed around the edges to maintain structure.
The pore size and pore volume of these protective masks can be evaluated by capillary flow porometry and mercury intrusion porosimetry, while moisture interaction with a mask can be evaluated by static volumetric water sorption isotherms. This report focusses on the physical characterization of a three-layer pleated mask and a molded cup mask.