Cloth face mask
Cloth face mask | |
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Other names | Fabric mask |
A cloth face mask is a mask made of common textiles, usually cotton, worn over the mouth and nose. Although they are less effective than surgical masks or N95 masks, they are used by the general public in household and community settings as perceived protection against both infectious diseases and particulate air pollution. For these reasons, cloth face masks are generally recommended by public health agencies only for disease source control in epidemic situations, but are not considered to be personal protective equipment.
They were routinely used by healthcare workers starting from the late 19th century until the mid 20th century. In the 1960s they fell out of use in the developed world in favor of modern surgical masks, but their use has persisted in developing countries. During the COVID-19 pandemic, their use in developed countries was revived as a last resort due to shortages of surgical masks and respirators.
Usage
Prior to the COVID-19 pandemic, reusable cloth face masks were predominantly used in developing countries and were especially prominent in Asia. Cloth face masks contrast with surgical masks and respirators such as N95 masks, which are made of nonwoven fabric formed through a melt blowing process, and are regulated for their effectiveness.[2] Like surgical masks, and unlike respirators, cloth face masks do not provide a seal around the face.[3]
In healthcare settings, they are used on sick patients as source control to reduce disease transmission through respiratory droplets, and by healthcare workers when surgical masks and respirators are unavailable. Cloth face masks are generally recommended for use only as a last resort if supplies of surgical masks and respirators are exhausted.[3] They are also used by the general public in household and community settings as perceived protection against both infectious diseases and particulate air pollution.[3][4]
Several types of cloth face masks are available commercially, especially in Asia.[4] Homemade masks can also be improvised using bandanas,[1] T-shirts,[1][2] handkerchiefs,[2] scarves,[2] or towels.[5]
Recommendations
The World Health Organization (WHO) recommends using masks with at least three layers of different materials. Two spunbond polypropylene layers are also believed to offer adequate filtration and breathability.[6]
When producing cloth face masks, two parameters should be considered: filtration efficiency of the material and breathability. The filter quality factor known as "Q" is commonly used as an integrated filter quality indicator. It is a function of filtration efficiency and breathability, with higher values indicating better performance. Experts recommend Q-factor of three or higher.[6]
Material (source) | Structure | Initial Filtration Efficiency (%) |
Initial Pressure drop (Pa) |
Filter quality factor, Q (kPa-1) |
---|---|---|---|---|
Polypropylene (interfacing material) | spunbond | 6 | 1.6 | 16.9 |
Cotton (sweater) | knit | 26 | 17 | 7.6 |
Cotton (T-shirt) | knit | 21 | 14.5 | 7.4 |
Polyester (toddler wrap) | knit | 17 | 12.3 | 6.8 |
Cotton (T-shirt) | woven | 5 | 4.5 | 5.4 |
Cellulose (tissue paper) | bonded | 20 | 19 | 5.1 |
Cellulose (paper towel) | bonded | 10 | 11 | 4.3 |
Silk (napkin) | woven | 4 | 7.3 | 2.8 |
Cotton (handkerchief) | woven | 1.1 | 9.8 | 0.48 |
Cotton, gauze | woven | 0.7 | 6.5 | 0.47 |
Nylon (exercise pants) | woven | 23 | 244 | 0.4 |
Effectiveness
Cloth face masks can be used for source control to reduce disease transmission arising from the wearer's respiratory droplets, but are not considered personal protective equipment for the wearer[7][8] as they typically have very low filter efficiency.[9][10] There are no standards or regulation for self-made cloth face masks.[10]
As of 2015, there had been no randomized clinical trials or guidance on the use of reusable cloth face masks.[3][5] Most research had been performed in the early 20th century, before disposable surgical masks became prevalent. One 2010 study found that 40–90% of particles in the 20–1000 nm range penetrated a cloth mask and other fabric materials.[9] The performance of cloth face masks varies greatly with the shape, fit, and type of fabric,[4] as well as the fabric fineness and number of layers.[5] As of 2006, no cloth face masks had been cleared by the U.S. Food and Drug Administration for use as surgical masks.[2]
An experiment carried out in 2013 by Public Health England, that country's health-protection agency, found that a commercially made surgical mask filtered 90% of virus particles from the air coughed out by participants, a vacuum cleaner bag filtered out 86%, a tea towel blocked 72% and a cotton t-shirt 51%—though fitting any diy mask properly and ensuring a good seal around the mouth and nose is crucial.[11][12] The use of common fabrics in making face masks has been tested.[13][14][15][16]
The primary role of masks worn by the general public is to "stop those who are already infected broadcasting the virus into the air around them."[12] This is of particular importance with the COVID-19 epidemic, as silent transmission seems to be a key feature of its rapid spread. For example, of the people on board the Diamond Princess cruise ship, 634 people were found to be infected—52% had no symptoms at the time of testing, including 18% who never developed symptoms.[17]
History
The first recorded use of a cloth face mask involved the French surgeon Paul Berger during an 1897 operation in Paris.[18] Masks came into use to protect against infectious diseases in the early 20th century.[3][5] A design by Wu Lien-teh, who worked for the Chinese Imperial Court during the 1910–11 Manchurian pneumonic plague outbreak, was the first that protected users from bacteria in empirical testing; it inspired masks used during the 1918 flu pandemic.[19] The first study of mask use by healthcare workers took place in 1918.[3][5] In the 1940s, face masks made from cheesecloth were used to protect nurses from tuberculosis.[20]
Cloth masks were largely supplanted by modern surgical masks made of nonwoven fabric in the 1960s,[2][5] although their use continued in developing countries.[3] They were used in Asia during the 2002–2004 SARS outbreak, and in West Africa during the 2013–2016 Ebola epidemic.[3]
COVID-19 pandemic
During the COVID-19 pandemic, multiple countries recommended the use of cloth masks to reduce the spread of the virus.
On June 5, WHO has changed its advice on face masks, recommending that fabric masks should be worn by general public where social distancing is not possible (e.g., on public transport, in shops or in other confined or crowded environments).[6][21]
References
- ^ a b c "Use of Cloth Face Coverings to Help Slow the Spread of COVID-19". U.S. Centers for Disease Control and Prevention. April 4, 2020. Retrieved April 5, 2020.
{{cite web}}
: CS1 maint: url-status (link) This article incorporates text from this source, which is in the public domain. - ^ a b c d e f Reusability of Facemasks During an Influenza Pandemic: Facing the Flu. Washington, D.C.: National Academies Press. July 24, 2006. pp. 6, 36–38. doi:10.17226/11637. ISBN 978-0-309-10182-0.
- ^ a b c d e f g h MacIntyre, C. R.; Chughtai, A. A. (April 9, 2015). "Facemasks for the prevention of infection in healthcare and community settings" (PDF). BMJ. 350 (apr09 1): h694. doi:10.1136/bmj.h694. ISSN 1756-1833. PMID 25858901.
- ^ a b c Shakya, Kabindra M.; Noyes, Alyssa; Kallin, Randa; Peltier, Richard E. (May 1, 2017). "Evaluating the efficacy of cloth facemasks in reducing particulate matter exposure" (PDF). Journal of Exposure Science & Environmental Epidemiology. 27 (3): 352–357. doi:10.1038/jes.2016.42. ISSN 1559-064X. PMID 27531371.
- ^ a b c d e f Chughtai, Abrar Ahmad; Seale, Holly; MacIntyre, Chandini Raina (June 19, 2013). "Use of cloth masks in the practice of infection control – evidence and policy gaps". International Journal of Infection Control. 9 (3). doi:10.3396/IJIC.v9i3.020.13. ISSN 1996-9783.
- ^ a b c d "Advice on the use of masks in the context of COVID-19". WHO. June 5, 2020.
- ^ "FAQs on the Emergency Use Authorization for Face Masks (Non-Surgical)". U.S. Food and Drug Administration. April 26, 2020. Retrieved May 21, 2020.
{{cite web}}
: CS1 maint: url-status (link) - ^ "Meat and Poultry Processing Workers and Employers". U.S. Centers for Disease Control and Prevention. April 26, 2020. Retrieved May 8, 2020.
{{cite web}}
: CS1 maint: url-status (link) - ^ a b Rengasamy S, Eimer B, Shaffer RE (2010). "Simple Respiratory Protection—Evaluation of the Filtration Performance of Cloth Masks and Common Fabric Materials Against 20–1000 nm Size Particles". Annals of Occupational Hygiene. 54 (7). Oxford University Press: 789–798. doi:10.1093/annhyg/meq044. ISSN 0003-4878.
- ^ a b "Using face masks in the community - Reducing COVID-19 transmission from potentially asymptomatic or pre-symptomatic people through the use of face masks". European Centre for Disease Prevention and Control. April 8, 2020. Retrieved May 21, 2020.
{{cite web}}
: CS1 maint: url-status (link) - ^ Davies, Anna; Thompson, Katy-Anne; Giri, Karthika; Kafatos, George; Walker, Jimmy; Bennett, Allan (May 22, 2013). "Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?". Disaster Medicine and Public Health Preparedness. 7 (4): 413–418. doi:10.1017/dmp.2013.43. ISSN 1935-7893. PMC 7108646. PMID 24229526.
- ^ a b "Should the public wear masks to slow the spread of SARS-CoV-2?". The Economist. ISSN 0013-0613. Retrieved April 20, 2020.
- ^ van der Sande, Marianne; Teunis, Peter; Sabel, Rob (July 9, 2008). Pai, Madhukar (ed.). "Professional and Home-Made Face Masks Reduce Exposure to Respiratory Infections among the General Population". PLoS ONE. 3 (7). Public Library of Science (PLoS): e2618. doi:10.1371/journal.pone.0002618. ISSN 1932-6203.
- ^ Davies, Anna; Thompson, Katy-Anne; Giri, Karthika; Kafatos, George; Walker, Jimmy; Bennett, Allan (May 22, 2013). "Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?". Disaster Medicine and Public Health Preparedness. 7 (4). Cambridge University Press (CUP): 413–418. doi:10.1017/dmp.2013.43. ISSN 1935-7893. PMC 7108646.
- ^ "Simple Respiratory Protection—Evaluation of the Filtration Performance of Cloth Masks and Common Fabric Materials Against 20–1000 nm Size Particles". The Annals of Occupational Hygiene. Oxford University Press (OUP). June 28, 2010. doi:10.1093/annhyg/meq044. ISSN 1475-3162.
- ^ Konda, Abhiteja; Prakash, Abhinav; Moss, Gregory A.; Schmoldt, Michael; Grant, Gregory D.; Guha, Supratik (April 24, 2020). "Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks". ACS Nano. American Chemical Society (ACS). doi:10.1021/acsnano.0c03252. ISSN 1936-0851.
- ^ "How important is "silent spreading" in the covid-19 epidemic?". The Economist. ISSN 0013-0613. Retrieved April 20, 2020.
- ^ Lowry, H. C. (November 1, 1947). "Some Landmarks in Surgical Technique". The Ulster Medical Journal. 16 (2): 102–13. PMC 2479244. PMID 18898288.
- ^ Wilson, Mark (March 24, 2020). "The untold origin story of the N95 mask". Fast Company. Retrieved March 27, 2020.
- ^ McNett, Esta H. (January 1, 1949). "The Face Mask in Tuberculosis: How the cheese-cloth face mask has been developed as a protective agent in tuberculosis". AJN the American Journal of Nursing. 49 (1): 32–36. ISSN 0002-936X.
- ^ "Coronavirus: WHO advises to wear masks in public areas". BBC News. June 6, 2020.