Being coughed has never been a pleasant experience, but 2020 has taken it to a whole new level.
Even with the vaccines launched, our main lines of defense against COVID-19 are still physical, moving away from each other and wearing a mask being the main one.
Unfortunately, there is still resistance in some circles to both measures. And even if you are completely on board, sometimes it can be easy to forget.
So get ready to be cashed. Engineers at the University of Edinburgh in the UK have conducted a study on masks and how effectively they stop large airways at different distances.
It is important to get rid of some misconceptions. SARS-CoV-2 virus particles are much smaller than holes in the fabric of a mask – but virus particles do not exist in isolation.
When you cough, talk or even breathe, small globes in your spit fly out of your mouth and land on everything in front of you and those globes can carry the virus.
Now, there is still some debate as to whether smaller aerosol particles are also a significant factor in the infection, but a mask is good enough to stop them.
When it comes to catching the virus (and almost all viruses), it is essential to make sure that you are exposed to as few virus particles as possible, so the fewer drops you encounter – small or large – the better.
The team compared how many of the larger spit balloons landed on surfaces at different distances while a person was wearing a mask from the one without a mask.
The results are both amazing and raw.
“Wearing a covering face has reduced the number of projected drops by less than 1,000 times,” writes the team, led by bioengineering Lucia Bandiera, in the study.
“I estimated that a person who lives 2 meters away [6.6 feet] from someone who coughs without a mask is exposed to more than 1,000 times more respiratory drops than from someone who is 0.5 meters away [1.6 feet] he wore a single-layer base mask. “
The team investigated this in several ways. A mannequin head that drew fluorescent water droplets in speech and cough simulations was observed with laser sheet lighting and UV light.
They also had six human volunteers, whose spit was caught on a microscope slide 5 centimeters (2 inches) from their mouths.
(Bandiera et al., Royal Society Open Science, 2020)
As you can see in the figure above, masks have made a real difference in the spread of these larger spitting drops. In fact, with each test, the number of drops decreased while wearing a mask (either single-layer cotton or surgical).
“When the mannequin wore either of the two face masks, I noticed that less than one in 1,000 particles escaped from both speech and coughing,” the team writes.
When they tested the six human volunteers to confirm, the results were just as good.
“We measured between 10 and 1,000 particles to speak and cough without a mask, respectively. Instead, we found zero particles with a surgical mask, both for speech and for coughing.”
Obviously, this is not the last word on this topic, nor does it make perfectly infallible masks. The study did not look at the smaller aerosol droplets, and the mannequin threw far more particles 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 spitting of your globes everywhere, which can make the difference in reducing the spread of COVID-19. We are all in this together.
The research was published in Royal Society Open Science.