Infrared-based visualization of exhalation flows while wearing protective face masks

Koroteeva, E. Yu.; Shagiyanova, A.

doi:10.1063/5.0076230

Cited by 15 publications

(9 citation statements)

References 32 publications

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“…Infrared imaging describes the spatial inhomogeneity based on temperature differences between ambient air and exhaled air or CO 2 absorption bands. 22 , 47 …”

Section: Resultsmentioning

confidence: 99%

“…Infrared imaging describes the spatial inhomogeneity based on temperature differences between ambient air and exhaled air or CO 2 absorption bands. 22,47 Other approaches measure in-mask CO Results demonstrate that dead space added by the FFR is similar in magnitude to the anatomical dead space. [Perhaps future combining this approach and computational fluid dynamics flow approaches may determine functionally effective mask dead space and CO concentration in-mask rose as high as 3% at moderate exercise 32 and 8% at maximal exhausting exercise.…”

Section: Resultsmentioning

confidence: 99%

“…Respiratory pattern and exhalation valves affect airflow distribution. Infrared imaging describes the spatial inhomogeneity based on temperature differences between ambient air and exhaled air or CO 2 absorption bands 22,47 …”

Section: Resultsmentioning

confidence: 99%

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Health effects of filtering facepiece respirators: Systematic review of pulmonary and cardiovascular effects

Harber

Beckett

2023

American J Industrial Med

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Filtering facepiece respirators (FFRs) were introduced to protect the wearer by removing small particles from inspired air. FFRs are now also used to reduce the spread of transmissible agents from the wearer and are worn outside traditional healthcare and other workplaces. The COVID‐19 pandemic increased concerns about potential adverse effects on wearers. A PUBMED query retrieved articles through June 2022. Abstracts and selected full‐text articles were systematically reviewed by the authors. This article focuses upon cardiopulmonary physiologic effects (e.g., ventilation, CO 2 elimination, oxygen uptake, and respiratory control) with emphasis upon current and potential research methods as well as summarizing results. 1985 records were identified, of which only 26% were published before 2020. FFR effects on CO 2 elimination appear more likely to be significant than effects on oxygenation or cardiovascular function. While FFRs appear well tolerated by healthy persons, more research is needed for those with pulmonary or cardiac disorders, and for children. Many traditional pulmonary exercise study methods require special care when applied to filtering facepiece respirators. Studying additional parameters may explain the paradox of many subjective discomfort reports despite very limited physiologic effects.

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“…Infrared imaging describes the spatial inhomogeneity based on temperature differences between ambient air and exhaled air or CO 2 absorption bands. 22 , 47 …”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Health effects of filtering facepiece respirators: Systematic review of pulmonary and cardiovascular effects

Harber

Beckett

2023

American J Industrial Med

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“…31 The approach is based on the detection of thermal radiation, 32 and uses near-infrared cameras to observe the warm exhaled airflows. 33 The third method, PIV, relies on seeding the surrounding air with particles which are tracked over time. A recent study used PIV to show how different transport mechanisms are responsible for the propagation of air over short and long distances for speaking and breathing scenarios.…”

Section: Introductionmentioning

confidence: 99%

Exhaled aerosols and saliva droplets measured in time and 3D space: Quantification of pathogens flow rate applied to SARS-CoV-2

Roth

Stiti

Frantz

et al. 2023

Preprint

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SARS-CoV-2 and its ever-emerging variants, are spread from host-to-host via expelled respiratory aerosols and saliva droplets. Knowing the number of virions which are exhaled by a person requires precise measurements of the size, count, velocity and trajectory of the virus-laden particles that are ejected directly from the mouth. These measurements are achieved in 3D, at 15000 images/second, and are applied when speaking, yelling, and coughing. In this study 33 events have been analysed by post-processing ~500000 images. Using these data, the flow rate of SARS-CoV-2 virions have been evaluated. At high concentrations, 10^7 virions/mL, it is found that 136 to 231 virions are ejected during a single cough, where the virion flow rate peak is capable of reaching 32 virions within a millisecond. This peak can reach tens of virions/ms when yelling, but reduced to only a few virions/ms when speaking. At medium concentrations, ~10^5 virions/mL, those results are hundreds of times lower. The total number of virions that are ejected when yelling at 110db, instead of speaking at 85db, increases by two to three fold. From the measured data analysed in this article, the flow rate of other diseases such as influenza, tuberculosis or measles, can also be estimated. As these data are openly accessible, they can be used by modellers for the simulation of saliva droplet transport and evaporation, allowing to further advance our understanding of airborne pathogen transmission.

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“…Some studies have focused on the dispersion of exhaled air from a person's cough when a surgical or N95 mask is worn. Various visualization methods, such as schlieren imaging, 34 , 35 light scattering, 35 infrared thermograph, 36 and laser‐based visualization, 37 , 38 , 39 have been reported. For example, Tang et al 34 used schlieren imaging to investigate the airflow generated by a cough.…”

Section: Introductionmentioning

confidence: 99%

Boundary conditions for exhaled airflow from a cough with a surgical orN95mask

et al. 2022

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Wearing surgical or N95 masks is effective in reducing the infection risks of airborne infectious diseases. However, in the literature there are no detailed boundary conditions for airflow from a cough when a surgical or N95 mask is worn. These boundary conditions are essential for accurate prediction of exhaled particle dispersion by computational fluid dynamics (CFD). This study first constructed a coughing manikin with an exhalation system to simulate a cough from a person. The smoke visualization method was used to measure the airflow profile from a cough. To validate the setup of the coughing manikin, the results were compared with measured data from subject tests reported in the literature. The validated coughing manikin was then used to measure the airflow boundary conditions for a cough when a surgical mask was worn and when an N95 mask was worn, respectively. Finally, this study applied the developed airflow boundary conditions to calculate person‐to‐person particle transport from a cough when masks are worn. The calculated exhaled particle patterns agreed well with the smoke pattern in the visualization experiments. Furthermore, the calculated results indicated that, when the index person wore a surgical and a N95 mask, the total exposure of the receptor was reduced by 93.0% and 98.8%, respectively.

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Infrared-based visualization of exhalation flows while wearing protective face masks

Cited by 15 publications

References 32 publications

Health effects of filtering facepiece respirators: Systematic review of pulmonary and cardiovascular effects

Health effects of filtering facepiece respirators: Systematic review of pulmonary and cardiovascular effects

Exhaled aerosols and saliva droplets measured in time and 3D space: Quantification of pathogens flow rate applied to SARS-CoV-2

Boundary conditions for exhaled airflow from a cough with a surgical orN95mask

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