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COVID Masks: Mechanistic View: Part 2: Fine Aerosol Emissions:
Masks may increase fine aerosol emissions from: 1) nebulization of large droplets into fine aerosols, or 2) friability of certain mask materials creating "aerosolized fomites."
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Here are the studies:
Masks may increase fine aerosol emissions from: 1) nebulization of large droplets into fine aerosols, or 2) friability of certain mask materials creating "aerosolized fomites."
Please share:
Here are the studies:
The question is whether facemasks are actually a source for viral aerosols by:
1) Masks get saturated by large "respiratory droplets" containing viral molecules. Air turbulence against trapped droplets may create aerosols that eventually diffuse around edges. Continued...
1) Masks get saturated by large "respiratory droplets" containing viral molecules. Air turbulence against trapped droplets may create aerosols that eventually diffuse around edges. Continued...
Trapped droplets potentially get pushed through the filter media of the mask, getting nebulized into aerosols.
Particles don't always stay in the mask:
Study: Ha'eri 1980
Title: The efficacy of standard surgical face masks: an investigation using "tracer particles"
Albumin tracer particles put inside a surgical mask were dispersed into the room by breathing.
https://europepmc.org/article/med/7379387
Study: Ha'eri 1980
Title: The efficacy of standard surgical face masks: an investigation using "tracer particles"
Albumin tracer particles put inside a surgical mask were dispersed into the room by breathing.
https://europepmc.org/article/med/7379387
Viral molecules can get airborne from air turbulence.
Study: Liu 2020
Title: Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals.
SARS-2-COV sub-micrometer aerosols not tightly bound to surfaces, get airborne when PPE is taken off. https://www.nature.com/articles/s41586-020-2271-3
Study: Liu 2020
Title: Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals.
SARS-2-COV sub-micrometer aerosols not tightly bound to surfaces, get airborne when PPE is taken off. https://www.nature.com/articles/s41586-020-2271-3
Diagram of filter media becoming a nebulizer: https://twitter.com/Kevin_McKernan/status/1320036566388121600
Another Possible source of Viral Aerosols:
2) "Aerosolized fomites" from the mask material itself (e.g. cotton or fabric) are shed during breathing. These tiny organic particles - fomites - are contaminated by even smaller viral molecules.
2) "Aerosolized fomites" from the mask material itself (e.g. cotton or fabric) are shed during breathing. These tiny organic particles - fomites - are contaminated by even smaller viral molecules.
Study: Asadi 2020
Friability of mask materials: Cotton or fabric may emit fine particles < 1 um, possibly spreading viral contamination. This study found breathing through DIY masks of cotton or fabric increased forward emission of fine aerosols. https://www.nature.com/articles/s41598-020-72798-7
Friability of mask materials: Cotton or fabric may emit fine particles < 1 um, possibly spreading viral contamination. This study found breathing through DIY masks of cotton or fabric increased forward emission of fine aerosols. https://www.nature.com/articles/s41598-020-72798-7
Study: Asadi 2020 (continued)
Cotton or cloth releases tiny organic material - aerosolized fomites - that can potentially serve as a conduit for viral molecules.
Cotton or cloth releases tiny organic material - aerosolized fomites - that can potentially serve as a conduit for viral molecules.
Study: Asadi 2020
Limitations:
Only measured 2 minutes of emissions
Only measured forward emissions; not emissions around edges; may underestimate total emissions vs no mask
Could not tell if medical-grade masks also increased aerosols when fully contaminated with droplets
Limitations:
Only measured 2 minutes of emissions
Only measured forward emissions; not emissions around edges; may underestimate total emissions vs no mask
Could not tell if medical-grade masks also increased aerosols when fully contaminated with droplets
Study: Asadi 2020
Title: Influenza A virus is transmissible via aerosolized fomites
Found that non-respiratory "aerosolized fomites" (organic debris) contaminated with a virus can infect other animals. May play large role in viral transmission. https://www.nature.com/articles/s41467-020-17888-w
Title: Influenza A virus is transmissible via aerosolized fomites
Found that non-respiratory "aerosolized fomites" (organic debris) contaminated with a virus can infect other animals. May play large role in viral transmission. https://www.nature.com/articles/s41467-020-17888-w
Conclusion:
So masks might capture some viral debris, but emissions might be in a more easily transported aerosol.
It's analogous to someone mistakenly power sanding lead paint to remove it. The total amount is reduced, but remaining portion is in a more hazardous form.
So masks might capture some viral debris, but emissions might be in a more easily transported aerosol.
It's analogous to someone mistakenly power sanding lead paint to remove it. The total amount is reduced, but remaining portion is in a more hazardous form.
Additional Information Welcome:
Studies measuring fine viral aerosols from masks, ideally including:
1) Fine aerosols < 1um
2) All directions, including leakage around mask
3) Enough time for full droplet contamination (e.g. 30 min)
Please reply or message me. Thank you.
Studies measuring fine viral aerosols from masks, ideally including:
1) Fine aerosols < 1um
2) All directions, including leakage around mask
3) Enough time for full droplet contamination (e.g. 30 min)
Please reply or message me. Thank you.
End Of Thread: Thank you for reading.
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