Surgical mask

For the mask approved for the prevention of infection from pathogens, like tuberculosis, see N95 respirator and FFP2.
Surgical mask
A surgical mask with hand-tied straps
Other namesProcedure mask, medical mask, isolation mask, laser mask, fluid-resistant masks, face mask

A surgical mask, also known by other names such as a medical face mask or procedure mask, is a personal protective equipment used by healthcare professionals that serves as a mechanical barrier that interferes with direct airflow in and out of respiratory orifices (i.e. nose and mouth). This helps reduce airborne transmission of pathogens and other aerosolized contaminants between the wearer and nearby people via respiratory droplets ejected when sneezing, coughing, forceful expiration or unintentionally spitting when talking, etc. Surgical masks may be labeled as surgical, isolation, dental or medical procedure masks.[1]

Although the material of which surgical masks are made will filter out some viruses and bacteria by trapping the aerosol suspended in breathed air, they only provide partial protection from airborne diseases because of the typically loose fit between the mask edges and the wearer's face.[2][3][4] Surgical masks are distinct from filtering respirators, such as those made to the American N95 standard, which are more airtight and purposefully designed to protect against finer airborne particles.

Comparison of breathing out without (top) and with (bottom) a mask. Note that without a mask jets of air are exhaled that can carry viruses and bacteria rapidly towards a person in front of the person breathing out. But with a mask these jets are blocked, meaning the air instead mostly rises due to convection. Note that although jets are blocked, the same amount of air moves in both cases, allowing the wearer to breathe easily.

Evidence from randomized controlled trials that surgical masks reduce infection from diseases such as influenza is weak.[5][6] Although a recent very large (over 300,000 people) study found some evidence that they reduced transmission in the community,[7] surgical masks can vary greatly in quality which may make these studies less useful.[3] The effect of surgical masks is partially attributed to filtering out some of aerosol particles that are how airborne diseases are transmitted. Surgical masks are highly variable[3] but the material of which they are made typically filter out more aerosol particles than do cloth masks but much less than does the material of which N95, FFP2 and similar masks, are made.[8] This combined with the poor fit suggests that surgical masks offer some protection to airborne diseases such as COVID-19 but less than do N95, FFP2 and similar masks.

There are standards for the materials masks are made from. For example, the European EN 14683 Type II standard requires the material of the mask to filter particles (mean diameter close to 3 micrometres) containing the bacterium Staphylococcus aureus.[9][10] The bacterial filtration efficiency of the mask material is the fractional reduction in the number of colony-forming units (CFUs) when the aerosol is passed through the material. For a Type II mask under this standard, the material must filter enough of the aerosol particles containing the bacteria to achieve a CFU reduction of at least 98%.

ASTM International has an F2100 standard[11] with similar bacterial filtering standard to the European Type II standard but in addition uses a test aerosol of 0.1 micrometre particles. The Level 3 standard F2100 standard requires that these particles must be filtered out with at least 98% efficiency. Neither the European nor the ASTM standard tests performance as worn, they just test the material — the difference being the air leakage. This is different to personal protection equipment standards such as N95 and FFP, which do test performance as worn.

Surgical masks are made of a nonwoven fabric created using a melt blowing process. They came into use in the 1960s and largely replaced cloth facemasks in developed countries.[12] The colored (usually dark blue, green, or occasionally yellow) side of the mask (fluid-repellant layer) is to be worn outwards, and the white side (absorbent layer) inwards.[13][14][15]

In some East Asian countries, masks have often customarily been worn by people who are sick in order to avoid spreading it, to protect against air pollution or allergens, as a fashion statement, or to deter social interaction.[16][17][18] The use of surgical masks during the COVID-19 pandemic was a subject of debate,[19] as mask shortage was a central issue.[20][21]

  1. ^ "N95 Respirators and Surgical Masks (Face Masks)". FDA. Retrieved 12 April 2020.
  2. ^ Sommerstein R, Fux CA, Vuichard-Gysin D, Abbas M, Marschall J, Balmelli C, et al. (July 2020). "Risk of SARS-CoV-2 transmission by aerosols, the rational use of masks, and protection of healthcare workers from COVID-19". Antimicrobial Resistance and Infection Control. 9 (1): 100. doi:10.1186/s13756-020-00763-0. PMC 7336106. PMID 32631450.
  3. ^ a b c Oberg T, Brosseau LM (May 2008). "Surgical mask filter and fit performance". American Journal of Infection Control. 36 (4): 276–282. doi:10.1016/j.ajic.2007.07.008. PMC 7115281. PMID 18455048.
  4. ^ Peeples L (October 2020). "Face masks: what the data say". Nature. 586 (7828): 186–189. Bibcode:2020Natur.586..186P. doi:10.1038/d41586-020-02801-8. PMID 33024333. S2CID 222183103.
  5. ^ Xiao J, Shiu EY, Gao H, Wong JY, Fong MW, Ryu S, Cowling BJ (May 2020). "Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings-Personal Protective and Environmental Measures". Emerging Infectious Diseases. 26 (5): 967–975. doi:10.3201/eid2605.190994. PMC 7181938. PMID 32027586.
  6. ^ Cite error: The named reference :7 was invoked but never defined (see the help page).
  7. ^ Abaluck J, Kwong LH, Styczynski A, Haque A, Kabir MA, Bates-Jefferys E, et al. (January 2022). "Impact of community masking on COVID-19: A cluster-randomized trial in Bangladesh". Science. 375 (6577): eabi9069. doi:10.1126/science.abi9069. PMC 9036942. PMID 34855513. S2CID 245933929.
  8. ^ Zangmeister CD, Radney JG, Vicenzi EP, Weaver JL (July 2020). "Filtration Efficiencies of Nanoscale Aerosol by Cloth Mask Materials Used to Slow the Spread of SARS-CoV-2". ACS Nano. 14 (7): 9188–9200. doi:10.1021/acsnano.0c05025. PMC 7341689. PMID 32584542.
  9. ^ Standards, European. "BS EN 14683:2019 Medical face masks. Requirements and test methods". www.en-standard.eu.
  10. ^ "Medical face masks - Requirements and test methods EN 14683:2019+AC:2019" (PDF).
  11. ^ "Standard Specification for Performance of Materials Used in Medical Face Masks". www.astm.org. Retrieved 2021-12-26.
  12. ^ Strasser BJ, Schlich T (July 2020). "A history of the medical mask and the rise of throwaway culture". Lancet. 396 (10243). The Lancet: 19–20. doi:10.1016/S0140-6736(20)31207-1. PMC 7255306. PMID 32450110.
  13. ^ Chua MH, Cheng W, Goh SS, Kong J, Li B, Lim JY, et al. (2020). "Face Masks in the New COVID-19 Normal: Materials, Testing, and Perspectives". Research. 2020: 7286735. Bibcode:2020Resea202086735C. doi:10.34133/2020/7286735. PMC 7429109. PMID 32832908.
  14. ^ Min J (1 June 2020). "Which Way Round Should a Surgical Face Mask Go?". SmartAirFilters.com. Retrieved 8 October 2020.
  15. ^ Min J (1 June 2020). "Does Wearing Surgical Masks With the Wrong Side Out Affect Their Ability to Capture Viruses?". SmartAirFilters.com. Retrieved 8 October 2020.
  16. ^ Yang J (19 November 2014). "A quick history of why Asians wear surgical masks in public". Quartz. Retrieved 28 March 2020.
  17. ^ "How surgical masks became a fashion statement". Dazed. 24 December 2015. Retrieved 28 March 2020.
  18. ^ "How K-Pop Revived Black Sickness Masks In Japan". Kotaku Australia. February 7, 2019. Archived from the original on March 18, 2019.
  19. ^ Ting V (4 April 2020). "To mask or not to mask: WHO makes U-turn while US, Singapore abandon pandemic advice and tell citizens to start wearing masks". South China Morning Post.
  20. ^ "Not Enough Face Masks Are Made In America To Deal With Coronavirus". NPR.org. 5 March 2020. Retrieved 10 April 2020.
  21. ^ "Chinese mask makers use loopholes to speed up regulatory approval". Financial Times. 1 April 2020. Retrieved 10 April 2020.