Filtration efficiency of surgical and FFP3 masks against composite dust

Abstract

The aim of this study was to investigate the protection efficiency of two types of face masks against composite dust and to characterize the particles that penetrated through the masks. Composite dust was created by grinding a commercial nano‐filled composite in a plexiglass box without using water cooling or high vacuum evacuation, in order to obtain a worst‐case exposure. Dust particles were collected using a personal inhalable aerosol sampler (IOM) fixed inside a custom‐made phantom head. Surgical and filtering facepiece (FFP3) masks were tested, and the situation without a mask served as control. The IOM sampler contained a cassette with two filters to collect large inhalable (4–100 µm) and respirable dust particles (1 µm) being seen when no mask was applied, whereas only nanoparticles could be detected when either type of face mask was applied. Even though FFP3 masks showed a higher filtration efficacy than surgical masks of the inhalable dust fraction, penetration of a small respirable particle fraction was inevitable for both masks.