Face coverings and respiratory tract droplet dispersion
This article has been Reviewed by the following groups
Listed in
- Evaluated articles (ScreenIT)
Abstract
Respiratory droplets are the primary transmission route for SARS-CoV-2, a principle which drives social distancing guidelines. Evidence suggests that virus transmission can be reduced by face coverings, but robust evidence for how mask usage might affect safe distancing parameters is lacking. Accordingly, we set out to quantify the effects of face coverings on respiratory tract droplet deposition. We tested an anatomically realistic manikin head which ejected fluorescent droplets of water and human volunteers, in speaking and coughing conditions without a face covering, or with a surgical mask or a single-layer cotton face covering. We quantified the number of droplets in flight using laser sheet illumination and UV-light for those that had landed at table height at up to 2 m. For human volunteers, expiratory droplets were caught on a microscope slide 5 cm from the mouth. Whether manikin or human, wearing a face covering decreased the number of projected droplets by less than 1000-fold. We estimated that a person standing 2 m from someone coughing without a mask is exposed to over 10 000 times more respiratory droplets than from someone standing 0.5 m away wearing a basic single-layer mask. Our results indicate that face coverings show consistent efficacy at blocking respiratory droplets and thus provide an opportunity to moderate social distancing policies. However, the methodologies we employed mostly detect larger (non-aerosol) sized droplets. If the aerosol transmission is later determined to be a significant driver of infection, then our findings may overestimate the effectiveness of face coverings.
Article activity feed
-
SciScore for 10.1101/2020.08.11.20145086: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement IRB: This research protocol was approved by the University of Edinburgh’s Human Research Ethical Review Committee and all human participants gave written informed consent.
Consent: This research protocol was approved by the University of Edinburgh’s Human Research Ethical Review Committee and all human participants gave written informed consent.Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
Software and Algorithms Sentences Resources Images were imported into Inkscape to reconstruct the continuous sample and to equalise the pictures across the whole sample. Inkscapesuggested: …SciScore for 10.1101/2020.08.11.20145086: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement IRB: This research protocol was approved by the University of Edinburgh’s Human Research Ethical Review Committee and all human participants gave written informed consent.
Consent: This research protocol was approved by the University of Edinburgh’s Human Research Ethical Review Committee and all human participants gave written informed consent.Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
Software and Algorithms Sentences Resources Images were imported into Inkscape to reconstruct the continuous sample and to equalise the pictures across the whole sample. Inkscapesuggested: (Inkscape, RRID:SCR_014479)All images were downscaled by a factor of five prior to their analysis in scikit-image, Python. Pythonsuggested: (IPython, RRID:SCR_001658)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We found bar graphs of continuous data. We recommend replacing bar graphs with more informative graphics, as many different datasets can lead to the same bar graph. The actual data may suggest different conclusions from the summary statistics. For more information, please see Weissgerber et al (2015).
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
-
-
SciScore for 10.1101/2020.08.11.20145086: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement This research protocol was approved by the University of Edinburgh’s Human Research Ethical Review Committee and all human participants gave written informed consent. Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable Accordingly, we performed experiments using four male and two female volunteers (aged between 30 and 45) to either read a sample script for three minutes or cough for one minute. Table 2: Resources
Software and Algorithms Sentences Resources Images were imported into Inkscape to reconstruct the continuous sample and to equalise the pictures across the whole sample. …SciScore for 10.1101/2020.08.11.20145086: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement This research protocol was approved by the University of Edinburgh’s Human Research Ethical Review Committee and all human participants gave written informed consent. Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable Accordingly, we performed experiments using four male and two female volunteers (aged between 30 and 45) to either read a sample script for three minutes or cough for one minute. Table 2: Resources
Software and Algorithms Sentences Resources Images were imported into Inkscape to reconstruct the continuous sample and to equalise the pictures across the whole sample. Inkscapesuggested: (Inkscape, RRID:SCR_014479)All images were downscaled by a factor of five prior to their analysis in scikit-image, Python. Pythonsuggested: (IPython, RRID:SCR_001658)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
About SciScore
SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.
-
