Coughing up has never been a pleasant experience, but 2020 has turned it into a whole new level of no.
Even with vaccines being rolled out, our main lines of defense against COVID-19 are still physical, with distance and mask wearing being the most important among them.
Unfortunately, in some circles there is still resistance to both measures. And even when you’re all the way on board, it can sometimes be easy to forget.
So prepare to be grossed out. Engineers at the University of Edinburgh in the UK have researched masks and how effectively these large breathing droplets stop at different distances.
It’s important to dispel some misconceptions right away. SARS-CoV-2 virus particles are much smaller than the holes in the fabric of a mask – but the virus particles do not exist on their own.
When you cough, talk, or even breathe, little blobs of your spit fly out of your mouth and land on what’s in front of you, and it’s those blobs that can carry the virus.
Now there is still some debate as to whether smaller aerosol particles are also a major cause of infection, but a mask is also pretty good for stopping them.
When it comes to catching the virus (and virtually all viruses), it’s important to make sure you’re exposed to as few of those virus particles as possible, so the fewer droplets – small or large – you come across, the better.
The team compared how many of the larger spits of spit from different distances landed on surfaces while one person was wearing a mask, versus the remainder maskless.
The results are both astonishing and crude.
“Wearing a face mask reduced the number of droplets projected by less than 1,000 times,” the team, led by bioengineer Lucia Bandiera, wrote in the study.
“We estimate that a person stands 2 meters [6.6 feet] someone who coughs without a mask is exposed to more than 1,000 times more drops of breath than someone standing 0.5 meters [1.6 feet] Get rid of wearing a standard single layer mask. “
The team has investigated this in a number of ways. A manikin firing fluorescent water droplets in speech and cough simulations was observed with laser sheet illumination and UV light.
They also had six human volunteers whose saliva was captured on a microscope slide 5 centimeters from their mouths.
(Bandiera et al., Royal Society Open Science, 2020)
As you can see in the image above, the masks really made a difference in the distribution of these larger droplets of spit. In fact, with each individual test, the droplet count decreased while wearing a mask (either single-ply cotton or surgical).
“When the doll was wearing one of the two face masks, we saw that less than one in 1,000 particles escaped for both speaking 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 1000 particles for speaking and coughing without a mask, respectively. Conversely, we found zero particles with the surgical mask, both for speaking and coughing.”
Of course, this isn’t the last word on this topic, nor does it make masks perfectly waterproof. The study didn’t look at the smaller aerosol droplets, and the manikin ejected particles for much longer than a human would – 60,000 coughs to be exact.
But it’s a good reminder that even a simple homemade mask can be incredibly effective at keeping your spit balls from getting all over the place, which can make a difference in reducing the spread of COVID-19. We are all in this together.
The research is published in Royal Society Open Science.