Respiratory Protection Against Nanoparticles: The Fit of Filtering Facepiece Respirators in the Context of Total Inward Leakage

Abstract The European standard EN 149:2001+A1:2009 specifies tests for filtering respiratory protective equipment (RPE). One of them is the total inward leakage (TIL) test designed to assess the fit of RPE and its performance in providing protection against harmful airborne particles and dust. The test is typically conducted using a sodium chloride aerosol with a mass median aerodynamic diameter of 0.6 µm. The objective of this study was to conduct TIL tests for the evaluation of the performance of high-quality filtering RPE against an aerosol containing reduced graphene oxide particles, considering the nanometric scale and varied shapes of these particles, and with particular attention to adequate fit. TIL was measured for four types of FFP2 respirators as well as four types of FFP3 respirators of various designs using a head-and-torso dummy that simulated a sequence of human movements consisting of head rotation (right-to-left), head tilt (up-and-down), and speech, followed by a rest period. TIL measurements followed a fit test performed using a PortaCount system (TSI, Inc., St. Paul, MN) and lasted 10 min in accordance with the exercise protocol specified in the standard EN 149. Analysis involved only particles no larger than 100 nm. The results showed that high-quality FFP3 respirators provide the highest level of protection, with an average TIL value of 0.75%. The study offers new insights into the appropriate fit and design of filtering facepiece respirators and contributes to minimizing the risk of leakage. It also demonstrates that the fit factor and filtering effectiveness influence measurements and TIL results for respirators challenged with a reduced graphene oxide aerosol. Graphical abstract