To reduce the spread of COVID-19, we wear face masks to protect those around us from exposure to our potentially infected respiratory droplets. But if you've rocked a neck cuff or headscarf for style or ease, new research actually doesn't offer you much protection at all.
Duke's scientists compared 14 different types of face coverings – including 2 and 3-layer fabric and surgical masks, various N95s, a neck cuff and a traditional headscarf. They measured how many droplets came through the fabric when the wearer spoke.
Their results, published in Science Advances: While some masks work quite well, bandanas offer almost no protection against the transmission of breath droplets. And the neck seal they tested actually let more droplets through than if they weren't wearing a mask at all.
Why gaiters and bandanas don't work well
The Duke team did not investigate exactly why some masks worked better than others. But the Type of substance and how tight the mask fits to your face are both Key components how effective There will be face covering, says lead study author Martin Fischer, Ph.D., associate research professor of chemistry at Duke.
Bandanas leave a large gap under your mouth for particles to leak out of when you speak or breathe.
And the material and weave of a neck seal – at least the team Fischer used, which was a single layer of polyester / spandex – splits larger droplets into several smaller ones, which actually increases the overall droplet count.
Smaller droplets not only create more droplets to breathe in, but also stay in the air longer than large ones thanks to gravity. This increases the risk of exposure to your surroundings even further if you cover your mouth with a gaiter while driving past someone on a narrow path or in a crowded subway car.
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So which face masks actually worked?
As for the most effective masks, Fischer's team found a customized N95 best, most likely because it is both dense and thick.
However, the ventilated version of an N95 mask performed very poorly. This is not surprising when you consider that the Centers for Disease Control and Prevention warned last week that masks with exhalation valves or vents (i.e., the face coverings you might have during construction) won't prevent the wearer from doing so To transmit COVID-19 to others. After all, just let all of your air out into the world.
The second best overall mask was a three-layer surgical mask followed by a three-layer cotton / poly blend (as a family member may have sewn for you). The more layers the better – three helped significantly reduce the number of breath droplets that could migrate through the layers compared to two-layer or single-layer cloth masks.
The bottom line
Customized N95 masks work best – but these should be reserved for healthcare workers, emphasizes Fischer. Cotton masks now block about 80 percent of the droplets, which is "perfectly fine" for everyday use, he adds. Opt for a three-tier variant if you can. (TBD on when ties are better than elastic, says Fischer.)
Perhaps surprisingly, if a gaiter is the only face covering available, you should use it anyway. Fischer quickly points out that they only investigated one type. Other brands and materials could perform better. But at least fold your gaiter in half or three times so that you have more than one layer in front of your mouth for added protection, he suggests.
The closer a mask fits your face and the more layers of fabric there are between your mouth and the outside world, the better the protection. (A good rule of thumb: if you can see light through the fabric, it doesn't offer much protection, says Fischer.)
Yes, these are two things that make it difficult to breathe out a mask when you're exercising or wearing it all day. But until we know more about who is a carrier of COVID-19, the goal of wearing a mask should be to protect others from your own breath droplets. And any mask is better than no mask.
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Our selection (not based on the study)
If you're a hardcore fitness fan who sweats regularly, try planning your workout outdoors in less congested areas outside of rush hour (i.e. avoiding parks). If you exercise in extremely hot and humid conditions, try the new Buff Filter Mask ($ 30). It comes with five replacement filters that block 98 percent of the particles in the air (they should be replaced after 24 hours), and the adjustable elastic bands on the back of the head keep it in place. Or, opt for the Asics Runners Face Cover (40 US -Dollar). It mitigates the spread of droplets by covering your nasal passage without affecting the breathability inside the mask. Specially placed air holes let air in but prevent your saliva from leaking out. These are not as easy as a N95, but these should also be reserved for healthcare workers. By being more strategic about where and when to exercise, in addition to wearing one of these masks, you will ultimately reduce your risk of catching and spreading COVID-19.
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