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Cited by 353Infection Control and VentilationAerosol Filtration and Electrostatic PrecipitationOccupational Health and Safety in Workplaces

Performance of an N95 filtering facepiece particulate respirator and a surgical mask during human breathing: two pathways for particle penetration

Open access
Grinshpun, Sergey A., Haruta, Hiroki, Eninger, Robert M., Reponen, Tiina, McKay, Roy T., Lee, Shu-An·2009·Journal of Occupational and Environmental Hygiene
DOI 10.1080/15459620903120086PMC PMC7196699
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Abstract

The protection level offered by filtering facepiece particulate respirators and face masks is defined by the percentage of ambient particles penetrating inside the protection device. There are two penetration pathways: (1) through the faceseal leakage, and the (2) filter medium. This study aimed at differentiating the contributions of these two pathways for particles in the size range of 0.03-1 microm under actual breathing conditions. One N95 filtering facepiece respirator and one surgical mask commonly used in health care environments were tested on 25 subjects (matching the latest National Institute for Occupational Safety and Health fit testing panel) as the subjects performed conventional fit test exercises. The respirator and the mask were also tested with breathing manikins that precisely mimicked the prerecorded breathing patterns of the tested subjects. The penetration data obtained in the human subject- and manikin-based tests were compared for different particle sizes and breathing patterns. Overall, 5250 particle size- and exercise-specific penetration values were determined. For each value, the faceseal leakage-to-filter ratio was calculated to quantify the relative contributions of the two penetration pathways. The number of particles penetrating through the faceseal leakage of the tested respirator/mask far exceeded the number of those penetrating through the filter medium. For the N95 respirator, the excess was (on average) by an order of magnitude and significantly increased with an increase in particle size (p < 0.001): approximately 7-fold greater for 0.04 microm, approximately 10-fold for 0.1 microm, and approximately 20-fold for 1 microm. For the surgical mask, the faceseal leakage-to-filter ratio ranged from 4.8 to 5.8 and was not significantly affected by the particle size for the tested submicrometer fraction. Facial/body movement had a pronounced effect on the relative contribution of the two penetration pathways. Breathing intensity and facial dimensions showed some (although limited) influence. Because most of the penetrated particles entered through the faceseal, the priority in respirator/mask development should be shifted from improving the efficiency of the filter medium to establishing a better fit that would eliminate or minimize faceseal leakage.

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Cites

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  • Future efforts in designing new respiratory protection means for different environments should be increasingly focused on the peripheral design rather than on the further improvement of the filter media.

    “the future efforts in designing new respiratory protection means for different environments should be increasingly focused on the peripheral design rather than on the further improvement of the filter media [30].”

    From Bacteria Filtration Efficiency for Different Types of Protective Face Masks (2023) · cites this paper as [30]

    The Summary and Practical Implications recommends prioritizing peripheral design over further filter-media improvements, but explicitly limits that recommendation to respiratory protection devices for health care environments. The citing sentence broadens it to different environments, which this study does not establish. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

  • N95 FFRs have shown less filter penetration, fewer face seal leaks, and less total inward leakage than surgical masks under laboratory conditions.

    “N95 FFRs have shown less filter penetration, fewer face seal leaks, and less total inward leakage than surgical masks under laboratory conditions (Lee et al., 2008;Grinshpun et al., 2009;Smith et al., 2016)”

    From Size-selective Assessment of Respirator Protection against Airborne Fungi and (1→3)-β-D-glucan in Farms (2018) · cites this paper as Grinshpun et al., 2009

  • SMs had greater particle penetration through filters and face seal leaks compared to N95 FFRs.

    “SMs had greater particle penetration through filters and face seal leaks compared to N95 FFRs.”

    From Size-selective Assessment of Respirator Protection against Airborne Fungi and (1→3)-β-D-glucan in Farms (2018) · cites this paper as Grinshpun et al., 2009

  • As SMs do not provide a good fitting to the facial surface, particle penetration through face seal leaks is far greater than through the normal filter.

    “As they do not provide a good fitting to the facial surface, particle penetration through face seal leaks is far greater than through the normal filter (Grinshpun et al., 2009).”

    From Size-selective Assessment of Respirator Protection against Airborne Fungi and (1→3)-β-D-glucan in Farms (2018) · cites this paper as Grinshpun et al., 2009

  • Inward leakage due to gaps in the fit has been demonstrated to play a critical role in the ability of a mask or respirator to protect against exposure to particulates.

    “Inward leakage due to gaps in the fit has been demonstrated to play a critical role in the ability of a mask or respirator to protect against exposure to particulates [4, 59, 82–84].”

    From The protective performance of reusable cloth face masks, disposable procedure masks, KN95 masks and N95 respirators: Filtration and total inward leakage (2021) · cites this paper as [82]

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Cites

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Research works printed but not linked: 3

  1. "Respirator Protection," Code of Federal Regulations Title 42, Part 84. 1995. pp. 30382-30383.
  2. "Respiratory Protection," Code of Federal Regulations Title 29, Part 1910.134. 1998. pp. 412-437.
  3. Myers, W.R., J. Allender, W. Iskander, and C. Stanley: Causes of in- facepiece sampling bias-I. Half-facepiece respirators. Ann. Occup. Hyg. 32(3):345-359 (1988).

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Related

Authors
Grinshpun, S. A., Haruta, H., Eninger, R. M., Reponen, T., McKay, R. T., & Lee, S.-A.
Affiliations
  • University of Cincinnati (US)
  • Koken (Japan) (JP)
  • Feng Chia University (TW)
ORCID
Venue
Journal of Occupational and Environmental Hygiene
Publisher
Informa UK Limited
Published
2009-09-09
Volume
6
Issue
10
Pages
593-603
ISSN
  • 1545-9624 (ISSN-L)
  • 1545-9632
DOI
10.1080/15459620903120086
PMC
PMC7196699
OpenAlex
W1994338141
Cited by
353
References
16
Citations by year
2026: 9 · 2025: 17 · 2024: 27 · 2023: 26 · 2022: 43 · 2021: 62 · 2020: 55 · 2019: 9 · 2018: 17 · 2017: 13 · 2016: 10 · 2015: 12 · 2014: 12 · 2013: 19 · 2012: 9
FWCI
5.89
Type
journal article
Language
en
Open access
Locations
  • Journal of Occupational and Environmental Hygiene (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • University of Cincinnati
  • Cardinal Health
Topics
  • Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Infection Control and Ventilation
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Aerosol Filtration and Electrostatic Precipitation
  • Health Sciences › Health Professions › Occupational Therapy › Occupational Health and Safety in Workplaces
Keywords
N95 respirators, surgical masks, particle penetration, respirator fit, submicron particles, breathing pattern, facial motion, respirator fit testing, personal protective equipment
MeSH terms
Adult, Female, Humans, Male, Masks, Middle Aged, Particle Size, Respiration, Respiratory Protective Devices, Occupational Exposure, Particulate Matter

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