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

Amy V Mueller; Loretta A Fernandez

Standard methods to test the fit and performance of respirators and masks designed to form a seal against the face, such as N95 masks and respirators used by firefighters, employ instruments that can concurrently count particles in air inside and outside of the masks while the subject moves his/her head through a series of positions (OSHA 1998) . Several instruments have been specifically designed to perform fit tests of respirators and tight-sealing facemasks (e.g., TSI PortaCount). These tools and methods have been modified in the past to collect particle filtration data for loose-fitting, surgical type masks (van der Sande et al. 2008) , revealing that head motions and positions do not significantly affect the performance of loose-fitting masks in terms of filtering out nano-sized particles. This suggests that a simplified mask testing protocol for loose-fitting masks can provide a representative measure of particle filtration efficacy, something critically needed given the highly varied results and protocol shortcomings noted in prior studies (Brosseau and Sietsema, 2020) .