Cargando…

On respiratory droplets and face masks

Face mask filters—textile, surgical, or respiratory—are widely used in an effort to limit the spread of airborne viral infections. Our understanding of the droplet dynamics around a face mask filter, including the droplet containment and leakage from and passing through the cover, is incomplete. We...

Descripción completa

Detalles Bibliográficos
Autores principales: Dbouk, Talib, Drikakis, Dimitris
Formato: Online Artículo Texto
Lenguaje:English
Publicado: AIP Publishing LLC 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7301882/
https://www.ncbi.nlm.nih.gov/pubmed/32574231
http://dx.doi.org/10.1063/5.0015044
_version_ 1783547770739621888
author Dbouk, Talib
Drikakis, Dimitris
author_facet Dbouk, Talib
Drikakis, Dimitris
author_sort Dbouk, Talib
collection PubMed
description Face mask filters—textile, surgical, or respiratory—are widely used in an effort to limit the spread of airborne viral infections. Our understanding of the droplet dynamics around a face mask filter, including the droplet containment and leakage from and passing through the cover, is incomplete. We present a fluid dynamics study of the transmission of respiratory droplets through and around a face mask filter. By employing multiphase computational fluid dynamics in a fully coupled Eulerian–Lagrangian framework, we investigate the droplet dynamics induced by a mild coughing incident and examine the fluid dynamics phenomena affecting the mask efficiency. The model takes into account turbulent dispersion forces, droplet phase-change, evaporation, and breakup in addition to the droplet–droplet and droplet–air interactions. The model mimics real events by using data, which closely resemble cough experiments. The study shows that the criteria employed for assessing the face mask performance must be modified to take into account the penetration dynamics of airborne droplet transmission, the fluid dynamics leakage around the filter, and reduction of efficiency during cough cycles. A new criterion for calculating more accurately the mask efficiency by taking into account the penetration dynamics is proposed. We show that the use of masks will reduce the airborne droplet transmission and will also protect the wearer from the droplets expelled from other subjects. However, many droplets still spread around and away from the cover, cumulatively, during cough cycles. Therefore, the use of a mask does not provide complete protection, and social distancing remains important during a pandemic. The implications of the reduced mask efficiency and respiratory droplet transmission away from the mask are even more critical for healthcare workers. The results of this study provide evidence of droplet transmission prevention by face masks, which can guide their use and further improvement.
format Online
Article
Text
id pubmed-7301882
institution National Center for Biotechnology Information
language English
publishDate 2020
publisher AIP Publishing LLC
record_format MEDLINE/PubMed
spelling pubmed-73018822020-06-18 On respiratory droplets and face masks Dbouk, Talib Drikakis, Dimitris Phys Fluids (1994) ARTICLES Face mask filters—textile, surgical, or respiratory—are widely used in an effort to limit the spread of airborne viral infections. Our understanding of the droplet dynamics around a face mask filter, including the droplet containment and leakage from and passing through the cover, is incomplete. We present a fluid dynamics study of the transmission of respiratory droplets through and around a face mask filter. By employing multiphase computational fluid dynamics in a fully coupled Eulerian–Lagrangian framework, we investigate the droplet dynamics induced by a mild coughing incident and examine the fluid dynamics phenomena affecting the mask efficiency. The model takes into account turbulent dispersion forces, droplet phase-change, evaporation, and breakup in addition to the droplet–droplet and droplet–air interactions. The model mimics real events by using data, which closely resemble cough experiments. The study shows that the criteria employed for assessing the face mask performance must be modified to take into account the penetration dynamics of airborne droplet transmission, the fluid dynamics leakage around the filter, and reduction of efficiency during cough cycles. A new criterion for calculating more accurately the mask efficiency by taking into account the penetration dynamics is proposed. We show that the use of masks will reduce the airborne droplet transmission and will also protect the wearer from the droplets expelled from other subjects. However, many droplets still spread around and away from the cover, cumulatively, during cough cycles. Therefore, the use of a mask does not provide complete protection, and social distancing remains important during a pandemic. The implications of the reduced mask efficiency and respiratory droplet transmission away from the mask are even more critical for healthcare workers. The results of this study provide evidence of droplet transmission prevention by face masks, which can guide their use and further improvement. AIP Publishing LLC 2020-06-01 /pmc/articles/PMC7301882/ /pubmed/32574231 http://dx.doi.org/10.1063/5.0015044 Text en Copyright © 2020 Author(s) Published under license by AIP Publishing. 1070-6631/2020/32(6)/063303/11/$30.00 All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license ( http://creativecommons.org/licenses/by/4.0/).
spellingShingle ARTICLES
Dbouk, Talib
Drikakis, Dimitris
On respiratory droplets and face masks
title On respiratory droplets and face masks
title_full On respiratory droplets and face masks
title_fullStr On respiratory droplets and face masks
title_full_unstemmed On respiratory droplets and face masks
title_short On respiratory droplets and face masks
title_sort on respiratory droplets and face masks
topic ARTICLES
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7301882/
https://www.ncbi.nlm.nih.gov/pubmed/32574231
http://dx.doi.org/10.1063/5.0015044
work_keys_str_mv AT dbouktalib onrespiratorydropletsandfacemasks
AT drikakisdimitris onrespiratorydropletsandfacemasks