Assessment of Fabric Masks as Alternatives to Standard Surgical Masks in Terms of Particle Filtration Efficiency

Amy V Mueller; Loretta A Fernandez

The purpose of this work was to develop a standardized method to compare the efficacy of sewn fabric facemasks (produced using a variety of patterns and materials) to standard surgical masks in terms of protecting the wearer from airborne particulates of the size range expected to carry viruses. By collecting data on the counts of particles (0.02 to >1 µm) from both sides of the mask while it is being worn, both the material and the fit of the masks are tested simultaneously, and a simplified protocol enables testing of a novel mask design within <2 hours. These tests provide a rapid screening tool to test a variety of mask designs produced from readily-available materials. By conducting separate tests for masks worn loosely (as designed) and for the masks held close to the face using a layer of nylon stocking (as recommended by (Cooper et al. 1983b) ), this work also allows for separate evaluation of the combined effect of mask fit and materials on overall filtration efficiency versus the efficiency of the materials alone.