In vivo protective performance of N95 respirator and surgical facemask
Abstract
BACKGROUND: The SARS outbreak in 2003 has spawned a major controversy concerning protective performance facemasks for healthcare workers. This study reports a study on in-vivo protective performance of surgical masks and N95 respirators. METHODS: Typical surgical masks and N95 respirators used in Hong Kong hospitals were tested in comparison with those treated with nano-functional materials (called nano-masks) on various physical properties and in-vivo wear filtration efficiency, as well as usability test in hospitals for surgical masks. RESULTS: Tests on physical properties showed that N95 respirators had significantly lower air permeability and water vapor permeability than surgical masks. The in-vivo filtration tests illustrated that N95 respirators filtered out 97% of potassium chloride (KCl) solution, while surgical masks filtered out 95% of KCl solution. Nano-masks show stronger water repellency and antibacterial activities, but no difference in usability, comparing with normal N95 and surgical masks. CONCLUSIONS: Surgical masks can provide in-vivo filtration protection of 95% filtration efficiency. N95 respirators provide higher in-vivo filtration efficiency of 97% with significant reduction of air permeability and water vapor permeability. Compared to normal surgical masks/respirators, the nano-masks can provide additional protective functions in stopping capillary diffusion and antibacterial activities.
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Surgical masks and N95 filtering facepiece respirators can provide protection in a relatively low viral aerosol loading environment.
“indicating that SMs and N95 FFRs can provide protection in a relatively low viral aerosol loading environment.”
Both N95 filtering facepiece respirators and surgical masks gave 95% or greater filtration efficiency, and N95 filtering facepiece respirators had about 2% filtration efficiency higher than surgical masks.
“Results showed that both N95 FFRs and SMs gave 95% or greater filtration efficiency, and N95 FFRs had about 2% filtration efficiency higher than the SMs”
SMs were found to be as effective as N95 FFRs against aerosol particles similar to the size of infectious aerosols.
“However, SMs were found to be as effective as N95 FFRs against aerosol particles similar to the size of infectious aerosols. (17,19,20)”
Wearing surgical or FFP2 masks substantially reduces the number of bioaerosol particles emitted from human respiration.
“wearing surgical or FFP2 masks substantially reduces the number of bioaerosol particles emitted from human respiration.”
From Bacteria Filtration Efficiency for Different Types of Protective Face Masks (2023) · cites this paper as [27]
The efficacy of the single-layer cloth mask is not as clear and complete for protection and prevention.
“the efficacy of the single-layer cloth mask is not as clear and complete for the protection and prevention that could be achieved [25-27].”
From Bacteria Filtration Efficiency for Different Types of Protective Face Masks (2023) · cites this paper as [27]
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References 17 · Cited by 159
- Authors
- Li, Y., Wong, T., Chung, J., Guo, Y. P., Hu, J. Y., Guan, Y. T., Yao, L., Song, Q. W., & Newton, E.
- Affiliations
- Hong Kong Polytechnic University (HK)
- Corresponding author
- Li, Y.
- Venue
- American Journal of Industrial Medicine
- Publisher
- Wiley
- Published
- 2006-11-10
- Volume
- 49
- Issue
- 12
- Pages
- 1056-1065
- ISSN
- 0271-3586 (ISSN-L)
- 1097-0274
- OpenAlex
- W2066012479
- Cited by
- 159
- References
- 17
- Citations by year
- 2026: 5 · 2025: 8 · 2024: 11 · 2023: 11 · 2022: 20 · 2021: 33 · 2020: 22 · 2019: 3 · 2018: 5 · 2017: 2 · 2016: 6 · 2015: 6 · 2014: 2 · 2013: 3 · 2012: 4
- FWCI
- 2.94
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- American Journal of Industrial Medicine (publishedVersion)
- PubMed (publishedVersion)
- PolyU Institutional Research Archive (Hong Kong Polytechnic University) (submittedVersion)
- Research Explorer (The University of Manchester) (submittedVersion)
- Topics
- Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Infection Control and Ventilation
- Physical Sciences › Engineering › Electrical and Electronic Engineering › Aerosol Filtration and Electrostatic Precipitation
- Physical Sciences › Materials Science › Polymers and Plastics › Textile materials and evaluations
- Keywords
- N95 respirators, surgical masks, air permeability, water vapor permeability, water repellency, antibacterial activity, SARS, healthcare workers, capillary diffusion
- MeSH terms
- Aerosols, Air Pollutants, Occupational, Filtration, Health Personnel, Humans, Influenza, Human, Masks, Particle Size, Permeability, Respiratory Protective Devices, Occupational Exposure, Infection Control, Inhalation Exposure, Severe Acute Respiratory Syndrome, Nanoparticles
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