Influence of Test Protocol on Filtration Efficiency of Medical Face Mask Material

Abstract Medical face masks are an efficient protective barrier against the propagation of bacteria and viruses in societies. The current European standard focuses on the bacterial filtration efficiency of the filtering material for a mean particle size of 3.0 µm in terms of droplets that are exhale...

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Main Authors: Aurélie Joubert, Ala Bouhanguel, Yves Andrès, Laurence Le Coq
Format: Article
Language:English
Published: Springer 2023-11-01
Series:Aerosol and Air Quality Research
Subjects:
Online Access:https://doi.org/10.4209/aaqr.230180
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author Aurélie Joubert
Ala Bouhanguel
Yves Andrès
Laurence Le Coq
author_facet Aurélie Joubert
Ala Bouhanguel
Yves Andrès
Laurence Le Coq
author_sort Aurélie Joubert
collection DOAJ
description Abstract Medical face masks are an efficient protective barrier against the propagation of bacteria and viruses in societies. The current European standard focuses on the bacterial filtration efficiency of the filtering material for a mean particle size of 3.0 µm in terms of droplets that are exhaled, but viruses that are inhaled can be transported by particles of sub-micron size. The filtration efficiency of medical face mask material was evaluated in a bench test from both unused charged and discharged masks. Several polydisperse test aerosols were used - DEHS, alumina, HOLI, NaCl, Staphylococcus epidermidis and Emesvirus zinderi (MS2) - produced by liquid atomization and/or powder dispersion, and sized by optical and aerodynamic counters or cascade impactors. The results have shown that the particle size distribution and charges for a given type of aerosol can differ depending on the generator used, in particular the wet or dry nature of generation. The results in the sub-micron size range for charged face mask material showed that the filtration efficiency of neutral aerosols was lower than that of charged aerosols due to the electrostatic forces, e.g., 92% versus 99% efficiency for DEHS and alumina respectively for a mean aerodynamic diameter of 0.6 µm. With the discharged face mask material, the filtration efficiency was degraded in the sub-micron size range for all types of aerosol tested: e.g., 30% versus 65% efficiency for a mean optical diameter of 0.25 µm respectively for DEHS and alumina. For particle sizes > 3 µm, the results indicated that the nature of the aerosol has little influence because particle collection is dominated by impaction and interception mechanisms. The tests with MS2 virus demonstrated a good fit with NaCl filtration efficiency expressed in aerodynamic diameters over a range between 0.65 and > 7 µm, for charged and discharged medical face mask materials.
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spelling doaj-art-0c99c29132c0466da7fdbcdd960ef9682025-02-09T12:24:17ZengSpringerAerosol and Air Quality Research1680-85842071-14092023-11-0124511610.4209/aaqr.230180Influence of Test Protocol on Filtration Efficiency of Medical Face Mask MaterialAurélie Joubert0Ala Bouhanguel1Yves Andrès2Laurence Le Coq3IMT Atlantique, GEPEAIMT Atlantique, GEPEAIMT Atlantique, GEPEAIMT Atlantique, GEPEAAbstract Medical face masks are an efficient protective barrier against the propagation of bacteria and viruses in societies. The current European standard focuses on the bacterial filtration efficiency of the filtering material for a mean particle size of 3.0 µm in terms of droplets that are exhaled, but viruses that are inhaled can be transported by particles of sub-micron size. The filtration efficiency of medical face mask material was evaluated in a bench test from both unused charged and discharged masks. Several polydisperse test aerosols were used - DEHS, alumina, HOLI, NaCl, Staphylococcus epidermidis and Emesvirus zinderi (MS2) - produced by liquid atomization and/or powder dispersion, and sized by optical and aerodynamic counters or cascade impactors. The results have shown that the particle size distribution and charges for a given type of aerosol can differ depending on the generator used, in particular the wet or dry nature of generation. The results in the sub-micron size range for charged face mask material showed that the filtration efficiency of neutral aerosols was lower than that of charged aerosols due to the electrostatic forces, e.g., 92% versus 99% efficiency for DEHS and alumina respectively for a mean aerodynamic diameter of 0.6 µm. With the discharged face mask material, the filtration efficiency was degraded in the sub-micron size range for all types of aerosol tested: e.g., 30% versus 65% efficiency for a mean optical diameter of 0.25 µm respectively for DEHS and alumina. For particle sizes > 3 µm, the results indicated that the nature of the aerosol has little influence because particle collection is dominated by impaction and interception mechanisms. The tests with MS2 virus demonstrated a good fit with NaCl filtration efficiency expressed in aerodynamic diameters over a range between 0.65 and > 7 µm, for charged and discharged medical face mask materials.https://doi.org/10.4209/aaqr.230180Test aerosolsMS2 virusElectrostatic chargesParticle collection mechanisms
spellingShingle Aurélie Joubert
Ala Bouhanguel
Yves Andrès
Laurence Le Coq
Influence of Test Protocol on Filtration Efficiency of Medical Face Mask Material
Aerosol and Air Quality Research
Test aerosols
MS2 virus
Electrostatic charges
Particle collection mechanisms
title Influence of Test Protocol on Filtration Efficiency of Medical Face Mask Material
title_full Influence of Test Protocol on Filtration Efficiency of Medical Face Mask Material
title_fullStr Influence of Test Protocol on Filtration Efficiency of Medical Face Mask Material
title_full_unstemmed Influence of Test Protocol on Filtration Efficiency of Medical Face Mask Material
title_short Influence of Test Protocol on Filtration Efficiency of Medical Face Mask Material
title_sort influence of test protocol on filtration efficiency of medical face mask material
topic Test aerosols
MS2 virus
Electrostatic charges
Particle collection mechanisms
url https://doi.org/10.4209/aaqr.230180
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