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> A cloth mask will not protect you against an aerosol "In unpublished work, Linsey Marr, an environmental engineer at Virginia Tech in Blacksburg, and her co

> A cloth mask will not protect you against an aerosol "In unpublished work, Linsey Marr, an environmental engineer at Virginia Tech in Blacksburg, and her colleagues found that even a cotton T-shirt can block half of inhaled aerosols and almost 80% of exhaled aerosols measuring 2 µm across. Once you get to aerosols of 4–5 µm, almost any fabric can block more than 80% in both directions, she says." "Benn worked with Danish engineers at her university to test their two-layered cloth mask design using the same criteria as for medical-grade ventilators. They found that their mask blocked only 11–19% of aerosols down to the 0.3 µm mark, according to Benn. But because most transmission is probably occurring through particles of at least 1 µm, according to Marr and Jimenez, the actual difference in effectiveness between N95 and other masks might not be huge." https://www.nature.com/articles/d41586-020-02801-8 https://www.nature.com/articles/d41586-020-02801-8

endisneigh 5y ago
On the other hand some researchers think cloth masks, specifically gaiter types, are worse than nothing. https://advances.sciencemag.org/content/6/36/eabd3083 https://advances.sciencemag.org/content/6/36/eabd3083 > A bigger droplet scatters more light than a smaller droplet. This insight is important to interpret the result of the neck gaiter. The neck gaiter has a larger transmission (110%; see Fig. 3A) than the control trial. We attribute this increase to the neck gaiter dispersing larger droplets into several smaller droplets, therefore increasing the droplet count. The histogram of the binary diameter for the neck gaiter supports this theory (see fig. S5).
- fighterpilot 5y ago
  That study shows that the large majority of the cloth masks tested were much better than nothing. See Fig 3.A. The only mask that was worse than nothing was the Neck Gaiter, but the difference was both clinically small as well as statistically insignificant.
  - endisneigh 5y ago
    I'm talking about and referred to [gaiter type] masks specifically.

endisneigh 5y ago

On the other hand some researchers think cloth masks, specifically gaiter types, are worse than nothing. https://advances.sciencemag.org/content/6/36/eabd3083 https://advances.sciencemag.org/content/6/36/eabd3083 > A bigger droplet scatters more light than a smaller droplet. This insight is important to interpret the result of the neck gaiter. The neck gaiter has a larger transmission (110%; see Fig. 3A) than the control trial. We attribute this increase to the neck gaiter dispersing larger droplets into several smaller droplets, therefore increasing the droplet count. The histogram of the binary diameter for the neck gaiter supports this theory (see fig. S5).

fighterpilot 5y ago
That study shows that the large majority of the cloth masks tested were much better than nothing. See Fig 3.A. The only mask that was worse than nothing was the Neck Gaiter, but the difference was both clinically small as well as statistically insignificant.
- endisneigh 5y ago
  I'm talking about and referred to [gaiter type] masks specifically.