Masks play an important role in helping to limit the spread of the novel Coronavirusand can save tens of thousands of lives Experts say in the US if everyone wears them in public.
Yes, some masks provide better protection than others. But that doesn’t mean wearing turtlenecks – stretchy fabrics that people, especially runners, pull up to cover their noses and mouths – worse than not wearing a mask, as some recent articles success.
These articles are based on a study published August 7 in the journal Scientific advancein which researchers tested a new method to evaluate the mask̵7;s effectiveness. In other words, it’s a study done to test a methodology. However, researchers did explore some of the mask’s effectiveness in a “proof of principle” trial, to assess whether they could use this particular method to measure the mask’s effectiveness. or not. To do that, they gave a small number of participants a try on a variety of masks.
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“The mask tests done here … should only serve as a demonstration,” the authors write in the article. “Variations between subjects are to be expected, for example due to physiological differences, suitability of the mask, head position, speech pattern, etc.”
In this setup, a person wears a mask and speaks in the direction of the laser beam set up inside a box that is expanded into a sheet of light – and droplets dripping out of the mouth and through the mask will scatter away. light, detected by mobile phone camera. A simple computer algorithm counts drops in a captured video. The researchers demonstrated their method with 15 different types of masks and face masks; one participant tried all of the masks and four people tried a subset of the masks. In each of the trials, researchers asked participants to say “stay healthy, everyone” five times, and measure the number of drops they emit.
The authors found that the number of droplets that escaped through the mask was very different. For example, they did not see “any significant drops” emanating from the N95 respirator, even though they were often intended for medical personnel, co-author Martin Fischer, a chemist and physicist at Duke University in North Carolina, said at one news summary today (August 13). Duke’s team also tested a variety of cotton masks and found that they blocked about 80% of water droplets from the mouth, Fischer said.
However, in establishing evidence of this principle, some masks seem to allow more drops than others. According to research, a person wearing a mask produces 10% more drops than a person without a mask. Researchers hypothesize that this may be because a gaiter mask separates large drops from the person’s mouth into smaller droplets, which increases their number. That’s “a bit unsettling”, since the droplets can remain in the air for longer and are easily carried away by the air currents, Fischer said.
Evidence “not at all”
That being said, the wearer was only tested on a single person, it’s likely that the difference between individual speakers will outweigh any discrepancies between the masks they noticed. Furthermore, the researchers tested a single collared jacket (one that is very thin and is made up of a mixture of 8% spandex and 92% polyester).
The public “absolutely shouldn’t” use this as evidence that people with neck gait are worse than not wearing a mask, Fischer said. “We tested a mask because we just had that mask lying around … there are a lot of other pedestrians out there,” some could have better protection, he said. Even the way people wear them can change their level of protection, he added.
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Some experts do not believe that in the first place, this particular neck produced more seeds.
“I’m not sure if they actually measured respiratory droplets,” said William Ristenpart, a chemical engineering professor at the University of California, Davis, who wasn’t involved in the study. Instead, the Duke team may have measured fabric particles such as dust from the mask. Ristenpart told Live Science: “Research from my team during the peer review now indicates that some fabrics contain a significant number of particles that interfere with the mask’s efficiency measurements.
Study lead author Dr Eric Westman, associate professor of medicine at Duke University, said there is still a lot we don’t know about the effectiveness of the mask and more testing is needed to determine what. there. Although this study does not prove anything about masks, such as face veils, people should “pause” if they are using flimsy face masks, such as “fabric. A layer of stretch, spandex, polyester that you can easily breathe through and blow out a candle, “Westman told Live Science. He noted that such masks would not provide good protection, while a double-layer mask, for example, might be better.
Another study, published June 30 in the journal Fluid physics used another method to evaluate the effectiveness of a facemask other than a medical mask: a masked or unmasked mannequin was connected to a fog generator. The team found that without the mask, water droplets could fly up to 3.7 meters from the mannequin, but with the mask, that distance was significantly reduced, according to a previous Live Science report.
The researchers found that a well-stitched and layered cotton mask reduces spread the most, but the cone-style mask works well too. A one-layer bandanna (made from stretchy t-shirt material) and a folded handkerchief are not as effective. Center for Disease Control and Prevention (CDC) recently update their instructions to warn not to use the respirator valve, which can protect the person wearing the mask and not others, according to another Live Science report.
There are still more questions than answers, but one of the key takeaways from this new study emphasizes that, “just speaking can spread this. [virus] to others, I don’t have to scream, I don’t have to sneeze or sneeze, ”said Westman.
Originally published on Live Science.