Characterization of expiration air jets and droplet size distributions immediately at the mouth opening

C. Y.H. Chao; M. P. Wan; L. Morawska; G. R. Johnson; Z. D. Ristovski; M. Hargreaves; K. Mengersen; S. Corbett; Y. Li; X. Xie; D. Katoshevski

doi:10.1016/j.jaerosci.2008.10.003

Characterization of expiration air jets and droplet size distributions immediately at the mouth opening

C. Y.H. Chao, M. P. Wan, L. Morawska, G. R. Johnson, Z. D. Ristovski, M. Hargreaves, K. Mengersen, S. Corbett, Y. Li, X. Xie, D. Katoshevski

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Abstract

Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 μm and it was 16.0 μm for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm^-3 per cough and 0.004-0.223 cm^-3 for speaking.

Original language	English
Pages (from-to)	122-133
Number of pages	12
Journal	Journal of Aerosol Science
Volume	40
Issue number	2
DOIs	https://doi.org/10.1016/j.jaerosci.2008.10.003
State	Published - 1 Jan 2009

Keywords

Coughing
Expiratory droplets
Interferometric Mie imaging
Particle image velocimetry
Speaking

ASJC Scopus subject areas

Environmental Engineering
Pollution
Mechanical Engineering
Fluid Flow and Transfer Processes
Atmospheric Science

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10.1016/j.jaerosci.2008.10.003

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title = "Characterization of expiration air jets and droplet size distributions immediately at the mouth opening",

abstract = "Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 μm and it was 16.0 μm for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm-3 per cough and 0.004-0.223 cm-3 for speaking.",

keywords = "Coughing, Expiratory droplets, Interferometric Mie imaging, Particle image velocimetry, Speaking",

author = "Chao, {C. Y.H.} and Wan, {M. P.} and L. Morawska and Johnson, {G. R.} and Ristovski, {Z. D.} and M. Hargreaves and K. Mengersen and S. Corbett and Y. Li and X. Xie and D. Katoshevski",

note = "Funding Information: This research was jointly supported by the Australian Research Council Discovery Project DP0558410 and Hong Kong RGC Grant 611505. The expiratory droplet investigation setup and other related laser safety installations were provided by the International Laboratory for Air Quality and Health, Queensland University of Technology. The IMI and PIV systems were provided by The Hong Kong University of Science and Technology. Technical support provided by the mechanical workshop of the Faculty of Science, Queensland University of Technology is greatly appreciated. ",

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doi = "10.1016/j.jaerosci.2008.10.003",

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volume = "40",

pages = "122--133",

journal = "Journal of Aerosol Science",

issn = "0021-8502",

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T1 - Characterization of expiration air jets and droplet size distributions immediately at the mouth opening

AU - Chao, C. Y.H.

AU - Wan, M. P.

AU - Morawska, L.

AU - Johnson, G. R.

AU - Ristovski, Z. D.

AU - Hargreaves, M.

AU - Mengersen, K.

AU - Corbett, S.

AU - Li, Y.

AU - Xie, X.

AU - Katoshevski, D.

N1 - Funding Information: This research was jointly supported by the Australian Research Council Discovery Project DP0558410 and Hong Kong RGC Grant 611505. The expiratory droplet investigation setup and other related laser safety installations were provided by the International Laboratory for Air Quality and Health, Queensland University of Technology. The IMI and PIV systems were provided by The Hong Kong University of Science and Technology. Technical support provided by the mechanical workshop of the Faculty of Science, Queensland University of Technology is greatly appreciated.

PY - 2009/1/1

Y1 - 2009/1/1

N2 - Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 μm and it was 16.0 μm for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm-3 per cough and 0.004-0.223 cm-3 for speaking.

AB - Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 μm and it was 16.0 μm for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm-3 per cough and 0.004-0.223 cm-3 for speaking.

KW - Coughing

KW - Expiratory droplets

KW - Interferometric Mie imaging

KW - Particle image velocimetry

KW - Speaking

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Characterization of expiration air jets and droplet size distributions immediately at the mouth opening

Abstract

Keywords

ASJC Scopus subject areas

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