A laboratory model demonstrating the protective effects of surgical masks, face shields, and a combination of both in a speaking simulation.
Aerosols
Nebulizer
Respiratory particles
Journal
American journal of infection control
ISSN: 1527-3296
Titre abrégé: Am J Infect Control
Pays: United States
ID NLM: 8004854
Informations de publication
Date de publication:
04 2021
04 2021
Historique:
received:
14
12
2020
revised:
08
01
2021
accepted:
11
01
2021
pubmed:
25
1
2021
medline:
25
6
2021
entrez:
24
1
2021
Statut:
ppublish
Résumé
The protection against aerosol transmission provided by masks vs face shields or in combination when speaking indoors is not well understood. To simulate a human source, an aerosol generating system was made using a bacterial suspension in a nebulizer attached to an oxygen cylinder. A fan connected to the nebulizer created aerosols. Transmitted aerosols were detected using blood agar plates at 0.1524 and 1.8288 meters from source, simulating exposed person. The study was performed under controlled conditions at room temperature in a biohazard hood with high-efficiency particulate air (HEPA) filter and UV light. When face shields were used alone, significant numbers of bacterial colonies grew on blood agar plates. When a mask used alone for both the subjects (source and exposed), the blood agar yielded minimal colony forming units at both distances. When face shields were used in combination with masks, no significant improvement was observed as compared to masks alone. Our results were similar to what have been observed in related studies. Surgical masks alone provided good protection, surpassing the protection provided by face shields alone. Both used together provided the best protection, although the combined protection was similar to surgical masks use alone.
Sections du résumé
BACKGROUND
The protection against aerosol transmission provided by masks vs face shields or in combination when speaking indoors is not well understood.
METHODS
To simulate a human source, an aerosol generating system was made using a bacterial suspension in a nebulizer attached to an oxygen cylinder. A fan connected to the nebulizer created aerosols. Transmitted aerosols were detected using blood agar plates at 0.1524 and 1.8288 meters from source, simulating exposed person. The study was performed under controlled conditions at room temperature in a biohazard hood with high-efficiency particulate air (HEPA) filter and UV light.
RESULTS
When face shields were used alone, significant numbers of bacterial colonies grew on blood agar plates. When a mask used alone for both the subjects (source and exposed), the blood agar yielded minimal colony forming units at both distances. When face shields were used in combination with masks, no significant improvement was observed as compared to masks alone.
DISCUSSION
Our results were similar to what have been observed in related studies.
CONCLUSIONS
Surgical masks alone provided good protection, surpassing the protection provided by face shields alone. Both used together provided the best protection, although the combined protection was similar to surgical masks use alone.
Identifiants
pubmed: 33485923
pii: S0196-6553(21)00021-3
doi: 10.1016/j.ajic.2021.01.012
pmc: PMC7826106
pii:
doi:
Substances chimiques
Aerosols
0
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
409-415Informations de copyright
Copyright © 2021 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
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