Should You Ditch Your Gaiter As A Face Mask Not So Fast?

August 22, 2020

Experts say that masks play a vital role in helping to curb the spread of the new coronavirus and could save tens of thousands of lives in the United States if everyone wore them in public.

Yes, some masks are more protective than others. But that doesn’t mean that people who wear neck pads – stretchy fabrics that runners, especially, pull up to cover their noses and mouths – are worse than wearing no masks at all, some recent news articles have suggested.

The news articles are based on a study published Aug. 7 in the journal Science Advances in which researchers tested a new method for assessing the effectiveness of face masks. In other words, it was a study conducted to test a method. However, the researchers did explore the effectiveness of some masks in a “proof-of-principle” test to assess whether they could use this particular method to measure the effectiveness of the masks. To do so, they had a handful of participants try out various types of masks.

“The mask tests conducted here … . should be used only as a demonstration,” the authors wrote in the paper.” Differences between subjects are to be expected, for example, due to differences in physiology, mask fit, head position, speech patterns, etc.”

In this setup, a person wearing a mask speaks in the direction of a laser beam set inside a box that is expanded into a sheet of light – droplets of water coming out of the mouth, scattering light through the mask, and detected with a cell phone camera. A simple computer algorithm counts the droplets in the recorded video. The researchers demonstrated their method with 15 different masks and visors; one participant tried all of them, and four tried a subset of the masks. In each trial, the researchers had participants say “Stay healthy, people” five times and measured the number of droplets they emitted.

The authors found that the number of droplets that escaped through the masks varied widely. For example, they did not see “any sizable droplet” emissions from the N95 respirator, although these should normally be reserved for health care workers, co-author Martin Fisher, a chemist and physicist at Duke University in North Carolina, said at a news conference today (Aug. 13). The Duke team also tested a series of cotton masks and found that they blocked about 80 percent of the droplets ejected from the mouth, Fisher said.

However, in this proof-of-principle setup, some masks appeared to allow more droplets to pass through than others. According to the study, Gator masks produced 10 percent more droplets than people who did not wear masks. The researchers speculate that this may be because the gaiter masks split the large droplets in a person’s mouth into smaller droplets, thus increasing their number. Fisher said this is “somewhat concerning” because the small droplets can linger in the air longer and be easily carried away by air currents.

“Definitely not” evidence.
That said, the hood was tested on only one person, making it likely that the differences between individual speakers would overwhelm any differences they noticed between the masks. What’s more, the researchers tested a single neck shroud (a very thin, 8 percent spandex and 92 percent polyester blend).

Fisher says the public “should never” use this as evidence that a neck guard is worse than not wearing a mask at all.” We tested one mask, because we just had that one lying around…. There are a lot of other straitjackets, “some of which may be more protective, he said. Even the way people wear them can change their protective qualities, he added.

Some experts aren’t convinced that this particular neck gaiter will produce more particles in the first place.

“I’m not sure if they actually measured respiratory droplets,” said William Ristenpater, a chemical engineering professor at the University of California, Davis, who was not involved in the study. Instead, the Duke team may have measured dusty fabric particles from the masks. “My group’s current peer-reviewed study suggests that some of the fabric shed large amounts of particles that confounded the mask efficacy measurements,” Ristenpart told Live Science.

There’s still a lot we don’t know about the efficiency of face masks, and more testing is needed to determine that, says study senior author Dr. Eric Westerman, an associate professor of medicine at Duke University. While the study doesn’t prove anything about face masks (like tights), if people are using a thin mask, such as a “one-ply, spandex, polyester stretch fabric, you can easily breathe through it and blow out candles through it,” Westman told Live Science. he noted that these types of masks may not be very protective, and that the Double-layer masks, for example, may be better.

Another study, published in the June 30 issue of the journal Physics of Fluids, used a different method to assess the effectiveness of non-medical masks: a mannequin with or without a mask attached to a fog machine. According to a previous report by Live Science, the team found that droplets could travel up to 12 feet (3.7 meters) from the mannequin without a mask, but that distance dropped significantly if the mask was on.

These researchers found that sewn cotton masks that fit snugly and have multiple layers were the most effective at reducing transmission, but conical masks also worked well. Single-layer hoods (made of stretchy T-shirt material) and folded handkerchiefs were not as effective. According to another Live Science report, the Centers for Disease Control and Prevention (CDC) recently updated their guidelines to warn against the use of masks with exhalation valves, which may protect the mask wearer but not others.

There are still more questions than answers, but one of the key takeaways from this new study emphasizes that “just by talking it’s possible to spread this [virus] to other people, I don’t have to yell, I don’t have to sneeze or cough,” Westman said.