Coughing has never been a pleasant experience, but by 2020 it has taken it to a whole new level.
Even with the deployment of vaccines, our main lines of defense against COVID-19 remain physical, the distances being with each other and the use of a mask.
Unfortunately, there is still resistance in some circles to these two measures. And even if you’re completely on board, it can sometimes be easy to forget it.
So get ready for revenue. Engineers at the University of Edinburgh in the UK have conducted a study on masks and the effectiveness of stopping large respiratory drops at various distances.
It is important to get rid of some misconceptions. SARS-CoV-2 virus particles are much smaller than the holes in the tissue of a mask, but the virus particles do not exist in isolation.
When you cough, talk, or even breathe, small balloons in your shotgun come out of your mouth and land on what is in front of you, and it is these balloons that can carry the virus.
Now, there is still some debate as to whether smaller aerosol particles are also an important factor in the infection, but a mask is also good enough to stop them.
When it comes to catching the virus (and almost all viruses), it’s key to make sure you’re exposed to as little of these virus particles as possible, so that the fewer drops (small or large) you find, the better.
The team compared how many of the larger spit balloons landed on surfaces from various distances while one person was wearing a mask compared to the rest of the masks.
The results are both amazing and gross.
“Wearing a covering face reduced the number of projected drops by less than 1,000 times,” the team writes in the study, led by bioengineer Lucia Bandiera.
“We estimated there was a 2 meter person [6.6 feet] if someone without a mask cough is exposed to more than 1,000 times more breath drops than someone who is 0.5 meters away [1.6 feet] with a basic single-layer mask. “
The team investigated it in several ways. A mannequin head was observed firing fluorescent drops of water in speech and cough simulations with laser foil illumination and UV light.
They also had six human volunteers, whose spit was trapped in a microscope slide 5 inches from their mouths.
(Bandiera et al., Royal Society Open Science, 2020)
As you can see in the figure above, the masks made a real difference in the spread of these larger spit drops. In fact, in each test, the number of drops plummeted while wearing a mask (either single-layer cotton or surgical).
“When the mannequin wore either of the two face masks, we observed that less than one in every 1,000 particles escaped to speak and cough,” the team writes.
When they tested the six human volunteers to confirm, the results were just as good.
“We measured between ten and a thousand particles of particles to speak and cough without a mask, respectively. In contrast, we found zero particles with the surgical mask, both for speaking and for coughing.”
Viously, obviously, this is not the last word on this subject, nor does it make masks perfectly infallible. The study did not examine the smallest aerosol droplets and the mannequin expelled the particles for much longer than a human would, 60,000 coughs to be exact.
But it’s a great reminder that even a simple homemade mask can be incredibly effective at limiting the arrival of spit balloons everywhere, which can make a difference in reducing the spread of COVID-19. We are all there together.
The research has been published in Royal Society Open Science.