1932

Abstract

Although face masks have been used for over a century to provide protection against airborne pathogens and pollutants, close scrutiny of their effectiveness has peaked in the past two years in response to the COVID-19 pandemic. The simplicity of face masks belies the complexity of the physical phenomena that determine their effectiveness as a defense against airborne infections. This complexity is rooted in the fact that the effectiveness of face masks depends on the combined effects of respiratory aerodynamics, filtration flow physics, droplet dynamics and their interactions with porous materials, structural dynamics, physiology, and even human behavior. At its core, however, the face mask is a flow-handling device, and in the current review, we take a flow physics–centric view of face masks and the key phenomena that underlie their function. We summarize the state of the art in experimental measurements, as well as the growing body of computational studies that have contributed to our understanding of the factors that determine the effectiveness of face masks. The review also lays out some of the important open questions and technical challenges associated with the effectiveness of face masks.

Loading

Article metrics loading...

/content/journals/10.1146/annurev-fluid-120720-035029
2023-01-19
2024-06-19
Loading full text...

Full text loading...

/deliver/fulltext/fluid/55/1/annurev-fluid-120720-035029.html?itemId=/content/journals/10.1146/annurev-fluid-120720-035029&mimeType=html&fmt=ahah

Literature Cited

  1. Abkarian M, Mendez S, Xue N, Yang F, Stone HA 2020. Speech can produce jet-like transport relevant to asymptomatic spreading of virus. PNAS 117:4125237–45
    [Google Scholar]
  2. Asadi S, Wexler AS, Cappa CD, Barreda S, Bouvier NM, Ristenpart WD. 2019. Aerosol emission and superemission during human speech increase with voice loudness. Sci. Rep. 9:12348
    [Google Scholar]
  3. Ather B, Mirza TM, Edemekong PF. 2020. Airborne precautions. StatPearls Treasure Island, FL: StatPearls https://www.ncbi.nlm.nih.gov/books/NBK531468/
    [Google Scholar]
  4. Bagheri G, Schlenczek O, Turco L, Thiede B, Stieger K et al. 2021a. Exhaled particles from nanometre to millimetre and their origin in the human respiratory tract. medRxiv 2021.10.01.21264333. https://doi.org/10.1101/2021.10.01.21264333
    [Crossref]
  5. Bagheri G, Thiede B, Hejazi B, Schlenczek O, Bodenschatz E 2021b. An upper bound on one-to-one exposure to infectious human respiratory particles. PNAS 118:49e2110117118
    [Google Scholar]
  6. Bahl P, de Silva C, Bhattacharjee S, Stone H, Doolan C et al. 2021. Droplets and aerosols generated by singing and the risk of coronavirus disease 2019 for choirs. Clin. Infect. Dis. 72:10e639–41
    [Google Scholar]
  7. Bałazy A, Toivola M, Adhikari A, Sivasubramani SK, Reponen T, Grinshpun SA. 2006. Do N95 respirators provide 95% protection level against airborne viruses, and how adequate are surgical masks?. Am. J. Infect. Control 34:251–57
    [Google Scholar]
  8. Bejan A. 2013. Convection Heat Transfer Hoboken, NJ: Wiley
    [Google Scholar]
  9. Bourouiba L. 2021. The fluid dynamics of disease transmission. Annu. Rev. Fluid Mech. 53:473–508
    [Google Scholar]
  10. Bourouiba L, Dehandschoewercker E, Bush JWM. 2014. Violent expiratory events: on coughing and sneezing. J. Fluid Mech. 745:537–63
    [Google Scholar]
  11. Bourrianne P, Kaneelil PR, Abkarian M, Stone HA. 2021a. Tracking the air exhaled by an opera singer. Phys. Rev. Fluids 6:11110503
    [Google Scholar]
  12. Bourrianne P, Xue N, Nunes J, Abkarian M, Stone HA. 2021b. Quantifying the effect of a mask on expiratory flows. Phys. Rev. Fluids 6:11110511
    [Google Scholar]
  13. Chao CYH, Wan MP, Morawska L, Johnson GR, Ristovski ZD et al. 2009. Characterization of expiration air jets and droplet size distributions immediately at the mouth opening. J. Aerosol Sci. 40:2122–33
    [Google Scholar]
  14. Chen CC, Willeke K. 1992. Aerosol penetration through surgical masks. Am. J. Infect. Control 20:4177–84
    [Google Scholar]
  15. Corum J, Zimmer C. 2022. Tracking omicron and other coronavirus variants. The New York Times accessed April 3. https://www.nytimes.com/interactive/2021/health/coronavirus-variant-tracker.html
    [Google Scholar]
  16. Darquenne C. 2012. Aerosol deposition in health and disease. J. Aerosol Med. Pulm. Drug Deliv. 25:3140–47
    [Google Scholar]
  17. Das S, Sarkar S, Das A, Das S, Chakraborty P, Sarkar J. 2021. A comprehensive review of various categories of face masks resistant to COVID-19. Clin. Epidemiol. Global Health 12:100835
    [Google Scholar]
  18. Dbouk T, Drikakis D. 2020. On respiratory droplets and face masks. Phys. Fluids 32:6063303
    [Google Scholar]
  19. Drewnick F, Pikmann J, Fachinger F, Moormann L, Sprang F, Borrmann S. 2021. Aerosol filtration efficiency of household materials for homemade face masks: influence of material properties, particle size, particle electrical charge, face velocity, and leaks. Aerosol Sci. Technol. 55:163–79
    [Google Scholar]
  20. Dua K, Hansbro PM, Wadhwa R, Haghi M, Pont LG, Williams KA, eds. 2020. Targeting Chronic Inflammatory Lung Diseases Using Advanced Drug Delivery Systems New York: Academic
    [Google Scholar]
  21. Duguid J. 1946. The size and the duration of air-carriage of respiratory droplets and droplet-nuclei. Epidemiol. Infect. 44:6471–79
    [Google Scholar]
  22. Fei J, Zhu Z, Pavlidis I. 2005. Imaging breathing rate in the CO2 absorption band. Proceedings of the 27th Annual International Conference of the IEEE Engineering in Medicine and Biology Society700–5 New York: IEEE
    [Google Scholar]
  23. Fennelly KP. 2020. Particle sizes of infectious aerosols: implications for infection control. Lancet Respir. Med. 8:9914–24
    [Google Scholar]
  24. Gralton J, Tovey E, McLaws ML, Rawlinson WD. 2011. The role of particle size in aerosolised pathogen transmission: a review. J. Infect. 62:11–13
    [Google Scholar]
  25. Greenhalgh T, Jimenez JL, Prather KA, Tufekci Z, Fisman D, Schooley R. 2021. Ten scientific reasons in support of airborne transmission of SARS-CoV-2. Lancet 397:102851603–5
    [Google Scholar]
  26. Grinshpun SA, Haruta H, Eninger RM, Reponen T, McKay RT, Lee SA. 2009. Performance of an N95 filtering facepiece particulate respirator and a surgical mask during human breathing: two pathways for particle penetration. J. Occup. Environ. Hyg. 6:10593–603
    [Google Scholar]
  27. Guarner J. 2020. Three emerging coronaviruses in two decades: the story of SARS, MERS, and now COVID-19. Am. J. Clin. Pathol. 153:4420–21
    [Google Scholar]
  28. Gupta JK, Lin CH, Chen Q 2009. Flow dynamics and characterization of a cough. Indoor Air 19:6517–25
    [Google Scholar]
  29. Hill WC, Hull MS, MacCuspie RI. 2020. Testing of commercial masks and respirators and cotton mask insert materials using SARS-CoV-2 virion-sized particulates: comparison of ideal aerosol filtration efficiency versus fitted filtration efficiency. Nano Lett. 20:107642–47
    [Google Scholar]
  30. Hinds WC. 1999. Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles New York: Wiley. , 2nd ed..
    [Google Scholar]
  31. Johnson G, Morawska L, Ristovski Z, Hargreaves M, Mengersen K et al. 2011. Modality of human expired aerosol size distributions. J. Aerosol Sci. 42:12839–51
    [Google Scholar]
  32. Ju JT, Boisvert LN, Zuo YY. 2021. Face masks against COVID-19: standards, efficacy, testing and decontamination methods. Adv. Colloid Interface Sci. 292:102435
    [Google Scholar]
  33. Kähler CJ, Hain R. 2020. Fundamental protective mechanisms of face masks against droplet infections. J. Aerosol Sci. 148:105617
    [Google Scholar]
  34. Karadimos A, Ocone R. 2003. The effect of the flow field recalculation on fibrous filter loading: a numerical simulation. Powder Technol. 137:3109–19
    [Google Scholar]
  35. Khosronejad A, Santoni C, Flora K, Zhang Z, Kang S et al. 2020. Fluid dynamics simulations show that facial masks can suppress the spread of COVID-19 in indoor environments. AIP Adv. 10:12125109
    [Google Scholar]
  36. Koh XQ, Sng A, Chee JY, Sadovoy A, Luo P, Daniel D. 2022. Outward and inward protection efficiencies of different mask designs for different respiratory activities. J. Aerosol Sci. 160:105905
    [Google Scholar]
  37. Kumar V, Nallamothu S, Shrivastava S, Jadeja H, Nakod P et al. 2020. On the utility of cloth facemasks for controlling ejecta during respiratory events. arXiv:2005.03444 [physics.med-ph]
  38. Kwong LH, Wilson R, Kumar S, Crider YS, Reyes Sanchez Y et al. 2021. Review of the breathability and filtration efficiency of common household materials for face masks. ACS Nano 15:45904–24
    [Google Scholar]
  39. Lai ACK, Poon CKM, Cheung ACT. 2012. Effectiveness of facemasks to reduce exposure hazards for airborne infections among general populations. J. R. Soc. Interface 9:70938–48
    [Google Scholar]
  40. Langmuir I. 1942. Report on smokes and filters Tech. Rep. 865, Sect. I, Part IV, US Off. Sci. Res. Dev. Washington, DC:
    [Google Scholar]
  41. Lee H, Kim S, Joo H, Cho HJ, Park K. 2022. A study on performance and reusability of certified and uncertified face masks. Aerosol Air Q. Res. 22:2210370
    [Google Scholar]
  42. Lee KW, Liu BYH. 1982. Theoretical study of aerosol filtration by fibrous filters. Aerosol Sci. Technol. 1:2147–61
    [Google Scholar]
  43. Lee SA, Grinshpun SA, Reponen T. 2008. Respiratory performance offered by N95 respirators and surgical masks: human subject evaluation with NaCl aerosol representing bacterial and viral particle size range. Ann. Occupat. Hyg. 52:3177–85
    [Google Scholar]
  44. Lei Z, Yang JJ, Zhuang Z. 2010. Contact pressure study of N95 filtering face-piece respirators using finite element method. Comput. Aided Des. Appl. 7:6847–61
    [Google Scholar]
  45. Lei Z, Yang JJ, Zhuang Z. 2012. Headform and N95 filtering facepiece respirator interaction: contact pressure simulation and validation. J. Occupat. Environ. Hyg. 9:146–58
    [Google Scholar]
  46. Lei Z, Yang JJ, Zhuang Z, Roberge R. 2013. Simulation and evaluation of respirator faceseal leaks using computational fluid dynamics and infrared imaging. Ann. Occupat. Hyg. 57:4493–506
    [Google Scholar]
  47. Leonard S, Atwood CW, Walsh BK, DeBellis RJ, Dungan GC et al. 2020. Preliminary findings on control of dispersion of aerosols and droplets during high-velocity nasal insufflation therapy using a simple surgical mask. Chest 158:31046–49
    [Google Scholar]
  48. Lepelletier D, Grandbastien B, Romano-Bertrand S, Aho S, Chidiac C et al. 2020. What face mask for what use in the context of the COVID-19 pandemic? The French guidelines. J. Hosp. Infect. 105:3414–18
    [Google Scholar]
  49. Lewis D et al. 2020. Mounting evidence suggests coronavirus is airborne—but health advice has not caught up. Nature 583:7817510–13
    [Google Scholar]
  50. Loudon RG, Roberts RM. 1967. Droplet expulsion from the respiratory tract. Am. Rev. Respir. Dis. 95:3435–42
    [Google Scholar]
  51. Mandavilli A. 2020. 239 experts with one big claim: The coronavirus is airborne. New York Times July 4
    [Google Scholar]
  52. Mao X, Hosoi AE. 2021. Estimating the filtration efficacy of cloth masks. Phys. Rev. Fluids 6:11114201
    [Google Scholar]
  53. Marr DR, Spitzer IM, Glauser MN. 2008. Anisotropy in the breathing zone of a thermal manikin. Exp. Fluids 44:4661–73
    [Google Scholar]
  54. Mittal R, Meneveau C, Wu W 2020a. A mathematical framework for estimating risk of airborne transmission of COVID-19 with application to face mask use and social distancing. Phys. Fluids 32:10101903
    [Google Scholar]
  55. Mittal R, Ni R, Seo JH. 2020b. The flow physics of COVID-19. J. Fluid Mech. 894:F2
    [Google Scholar]
  56. Morawska L, Milton DK. 2020. It is time to address airborne transmission of coronavirus disease 2019 (COVID-19). Clin. Infect. Dis. 71:92311–13
    [Google Scholar]
  57. Mussap CJ. 2019. The plague doctor of Venice. Int. Med. J. 49:5671–76
    [Google Scholar]
  58. Oberg T, Brosseau LM. 2008. Surgical mask filter and fit performance. Am. J. Infect. Control 36:4276–82
    [Google Scholar]
  59. Pan J, Harb C, Leng W, Marr LC. 2021. Inward and outward effectiveness of cloth masks, a surgical mask, and a face shield. Aerosol Sci. Technol. 55:6718–33
    [Google Scholar]
  60. Papineni RS, Rosenthal FS. 1997. The size distribution of droplets in the exhaled breath of healthy human subjects. J. Aerosol Med. 10:2105–16
    [Google Scholar]
  61. Paysan P, Knothe R, Amberg B, Romdhani S, Vetter T. 2009. A 3D face model for pose and illumination invariant face recognition. 2009 Sixth IEEE International Conference on Advanced Video and Signal Based Surveillance296–301 New York: IEEE
    [Google Scholar]
  62. Perić R, Perić M. 2020. Analytical and numerical investigation of the airflow in face masks used for protection against COVID-19 virus—implications for mask design and usage. J. Appl. Fluid Mech. 13:61911–23
    [Google Scholar]
  63. Pippin DJ, Verderame RA, Weber KK. 1987. Efficacy of face masks in preventing inhalation of airborne contaminants. J. Oral Maxillofac. Surg. 45:4319–23
    [Google Scholar]
  64. Pöhlker ML, Krüger OO, Förster JD, Berkemeier T, Elbert W et al. 2021. Respiratory aerosols and droplets in the transmission of infectious diseases. arXiv:2103.01188 [physics.med-ph]
  65. Raffel M, Willert CE, Scarano F, Kähler CJ, Wereley ST, Kompenhans J. 2018. Particle Image Velocimetry Cham, Switz: Springer Int.
    [Google Scholar]
  66. Randall K, Ewing ET, Marr LC, Jimenez J, Bourouiba L. 2021. How did we get here: What are droplets and aerosols and how far do they go? A historical perspective on the transmission of respiratory infectious diseases. Interface Focus 11:620210049
    [Google Scholar]
  67. Settles GS. 2001. Schlieren and Shadowgraph Techniques Berlin: Springer
    [Google Scholar]
  68. Sharma S, Pinto R, Saha A, Chaudhuri S, Basu S. 2021. On secondary atomization and blockage of surrogate cough droplets in single- and multilayer face masks. Sci. Adv. 7:10eabf0452
    [Google Scholar]
  69. Smith JD, MacDougall CC, Johnstone J, Copes RA, Schwartz B, Garber GE. 2016. Effectiveness of N95 respirators versus surgical masks in protecting health care workers from acute respiratory infection: a systematic review and meta-analysis. CMAJ 188:8567–74
    [Google Scholar]
  70. Solano T, Mittal R, Shoele K. 2021. One size fits all? A simulation framework for face-mask fit on population-based faces. PLOS ONE 16:6e0252143
    [Google Scholar]
  71. Solano T, Ni C, Mittal R, Shoele K. 2022. Perimeter leakage of face masks and its effect on the mask's efficacy. Phys. Fluids 34:5051902
    [Google Scholar]
  72. Steinle S, Sleeuwenhoek A, Mueller W, Horwell CJ, Apsley A et al. 2018. The effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation. Part II: total inward leakage tests. Int. J. Hyg. Environ. Health 221:6977–84
    [Google Scholar]
  73. Tang JW, Liebner TJ, Craven BA, Settles GS. 2009. A schlieren optical study of the human cough with and without wearing masks for aerosol infection control. J. R. Soc. Interface 6:Suppl. 6S727–36
    [Google Scholar]
  74. Tang JW, Marr LC, Li Y, Dancer SJ. 2021. COVID-19 has redefined airborne transmission. BMJ 373:n913
    [Google Scholar]
  75. Tuomi T. 1985. Face seal leakage of half masks and surgical masks. Am. Ind. Hyg. Assoc. J. 46:6308–12
    [Google Scholar]
  76. van der Sande M, Teunis P, Sabel R. 2008. Professional and home-made face masks reduce exposure to respiratory infections among the general population. PLOS ONE 3:7e2618
    [Google Scholar]
  77. Van Turnhout J, Hoeneveld W, Adamse JWC, Van Rossen LM. 1981. Electret filters for high-efficiency and high-flow air cleaning. IEEE Trans. Ind. Appl.2240–48
    [Google Scholar]
  78. VanSciver M, Miller S, Hertzberg J. 2011. Particle image velocimetry of human cough. Aerosol Sci. Technol. 45:3415–22
    [Google Scholar]
  79. Verma S, Dhanak M, Frankenfield J. 2020. Visualizing the effectiveness of face masks in obstructing respiratory jets. Phys. Fluids 32:6061708
    [Google Scholar]
  80. Wang CC, Prather KA, Sznitman J, Jimenez JL, Lakdawala SS et al. 2021. Airborne transmission of respiratory viruses. Science 373:6558eabd9149
    [Google Scholar]
  81. Wells WF. 1934. On air-borne infection: study II. Droplets and droplet nuclei. Am. J. Epidemiol. 20:3611–18
    [Google Scholar]
  82. Xi J, Si XA, Nagarajan R. 2020. Effects of mask-wearing on the inhalability and deposition of airborne SARS-CoV-2 aerosols in human upper airway. Phys. Fluids 32:12123312
    [Google Scholar]
  83. Xie X, Li Y, Chwang A, Ho P, Seto W. 2007. How far droplets can move in indoor environments—revisiting the Wells evaporation–falling curve. Indoor Air 17:3211–25
    [Google Scholar]
  84. Xu C, Nielsen PV, Liu L, Jensen RL, Gong G. 2017. Human exhalation characterization with the aid of schlieren imaging technique. Build. Environ. 112:190–99
    [Google Scholar]
  85. Zangmeister CD, Radney JG, Vicenzi EP, Weaver JL. 2020. Filtration efficiencies of nanoscale aerosol by cloth mask materials used to slow the spread of SARS-CoV-2. ACS Nano 14:79188–200
    [Google Scholar]
  86. Zhang G, Quetzeri-Santiago MA, Stone CA, Botto L, Castrejón-Pita JR. 2018. Droplet impact dynamics on textiles. Soft Matter 14:408182–90
    [Google Scholar]
  87. Zhu S, Kato S, Yang JH. 2006. Study on transport characteristics of saliva droplets produced by coughing in a calm indoor environment. Build. Environ. 41:121691–702
    [Google Scholar]
/content/journals/10.1146/annurev-fluid-120720-035029
Loading
/content/journals/10.1146/annurev-fluid-120720-035029
Loading

Data & Media loading...

  • Article Type: Review Article
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error