Measuring source control efficacy of different fitted masks for sub-micron aerosols

Abstract

Abstract SARS-CoV-2, as with other mucosal respiratory viruses, can be spread by both respiratory droplets and aerosols. We examined the filtration efficiency of fitted surgical, KN95, and N95 masks as source control for particle sizes in the 0.2 to 1 micron range. Barrier methods with higher filtration efficacy demonstrated greater filtration of sub-micron particles. However, once steady state was reached, the filtration efficacy was equivalent across the entire spectrum of sub-micron particle sizes tested. Aided by flow visualization, the analysis of the results show that the mask efficiency is driven by leakages despite “pinching” of a high quality form at the nose.