You may have seen posters appearing around the village at bus shelters and elsewhere suggesting they are dangerous to the wearer. Wearing a facemask is about one thing: providing some degree of protection to others from your own exhalation in confined spaces or when otherwise in close proximity to others.
A couple of things to note if you are inclined to take the points in these posters at all seriously:
- The last point on the posters suggests that there have been no peer reviewed studies of mask effectiveness but interestingly does not cite any peer reviewed studies for the contrary arguments or any of the other five assertions made. You may like to consider the following which appears to be based on verifiable science:
Who knew tissues and handkerchiefs worked…when they are used?
Relative scales (or orders of magnitude) are the key. As beautifully explained by Palli Thordarson. The SARS-CoV-19 and most viruses fall below the “polio virus” in size, as shown in the graphic above.
Molecules like O₂ – Oxygen (made of two atoms) or CH₄ – Methane (made of five atoms) are about the size of “atom” in the same graphic.
Along with oxygen, carbon dioxide molecules are also tiny, far smaller than droplets containing coronavirus which the masks are designed to stop – and won’t be trapped by a breathable material, particularly during relatively short periods like a bus journey.
‘SARS-CoV-2 particles do not float freely in the air. They are expelled as relatively large droplets, which research shows are easily caught by a simple cloth or paper mask. If an infected person doesn’t wear a mask, their droplets quickly evaporate into smaller droplet nuclei, which are harder to filter with a cloth mask. However there are some cloth mask designs which can do a very good job of this too.‘
from Particle sizes for mask filtration – https://www.fast.ai
Brownian Motion (the random motion of particles suspended in a medium, a liquid or a gas).
- Take a look at this video in which a doctor debunks the ‘oxygen depletion’ assertion and by implication, all of the other points made in the posters.