The reports of the demise of the neck gaiter have been greatly exaggerated.
A gaiter is a tube of fabric worn around the neck, often to keep skiers or runners warm in cold weather. But during the coronavirus pandemic, lightweight neck gaiters have been popular with runners, cyclists and people with beards because they can be pulled up to cover the nose and the mouth and used as a mask.
But in recent days, there has been a backlash against the gaiter. It started after a small study from Duke University demonstrated a new, inexpensive testing method for masks that uses lasers and phone cameras.
But in one part of the study, a neck gaiter performed poorly when a person wearing a gaiter said the words “Stay healthy, people” five times. During that test, the scientists observed a slight increase in the number of expelled saliva particles when the person wore the gaiter than when the wearer wore nothing at all. However, the technique they used was not a reliable way to measure particles, and it was not a statistically meaningful finding. Still, the study’s authors hypothesized that wearing a neck gaiter might cause more small droplets to spew through the fabric, not fewer.
A wave of reports on news sites and social media quickly followed. “Wearing a neck gaiter could be worse than wearing no mask at all,” read the headline in The Washington Post. (Read it here in The Seattle Times.)
Even the study’s authors said their data had been misconstrued. “Our intent was not to say this mask doesn’t work, or never use neck gaiters,” said Martin Fischer, an associate research professor in the department of chemistry at Duke and a co-author of the study. “This was not the main part of the paper.”
The suggestion that any mask can create more droplets than it stops doesn’t sound plausible to aerosol scientists, who test mask materials using special instruments that can measure microscopic particles. A number of variables, such as the volume of the mask wearer’s voice and whether the mask has become moist, might explain why the Duke study showed unusual results during the single gaiter test.
“The statistics of one don’t tell you very much,” said Richard C. Flagan, an aerosol scientist and engineering professor at California Institute of Technology. “Did he have more mucus on his vocal cords when he said it that time than other times? What might have caused the difference? You really don’t know from a single test.”
Mask testing has consistently shown that any face covering will block at least a small percentage of droplets generated when we speak or cough. The notion that a fabric gaiter will instead create more particles by splicing big droplets into smaller droplets is unlikely, experts say.
“The fabrics are not acting as a sharp sieve,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who is one of the world’s leading authorities on aerosols. “That’s not how filtration works.”
But rather than speculate, Dr. Marr worked with Jin Pan, a Virginia Tech graduate student who studies biological particles, to test two types of gaiters using methods similar to those required by the National Institute for Occupational Safety and Health for testing masks.
They decided to use foam heads to test gaiters as they are worn in real life, rather than tearing up a gaiter and testing just a small piece of fabric. One gaiter was a single-layer fabric made of 100 percent polyester. The other was a two-layer gaiter, made with 87 percent polyester and 13 percent elastane, a material often called spandex or Lycra.
The researchers used a liquid salt solution and a medical nebulizer to simulate saliva and to direct the particles through a tube in the foam head with a gaiter placed over the nose and the mouth. Special instruments measured the quantity and the size of droplets that were able to sneak through the mask.
Both gaiters prevented 100 percent of very large, 20-micron droplets from splattering another foam head just 30 centimeters away. Both masks blocked 50 percent or more of one-micron aerosols. The single layer gaiter blocked only 10 percent of 0.5-micron particles, while the two-layer gaiter blocked 20 percent. Notably, when the single-layer gaiter was doubled, it blocked more than 90 percent of all particles measured. By comparison, a homemade cotton T-shirt mask, recommended by the Centers for Disease Control and Prevention, blocked about 40 percent of the smallest particles.
Tests show wide variation in how much protection cloth masks provide. Some homemade masks perform far better than the gaiters tested in the Virginia Tech study, and some perform worse. Overall, tests of fabric masks have shown that two layers are better than one, and that a snug fitting mask with no gaps is best. Most experts agree that the average mask wearer doesn’t need medical-grade protection, and that any face covering, combined with social distancing, probably offers adequate protection for the average person against spreading or contracting the coronavirus.
“I’ve been recommending neck gaiters, and my kids wear neck gaiters,” Dr. Marr said. “There’s nothing inherent about a neck gaiter that should make it any worse than a cloth mask. It comes down to the fabric and how well it fits.”
The concern about the publicity surrounding the Duke study is that it might prompt people who prefer neck gaiters to stop wearing them or any other face covering. Others might shame someone for wearing a neck gaiter if they believe it might do more harm than good.
“We should be encouraging people to use the most effective masks that are practical for community settings, but in general, any face covering is probably better than none,” said Julia Marcus, an infectious disease epidemiologist and an assistant professor in the department of population medicine at Harvard Medical School. “The more that people see face coverings out in the world, regardless of what kind, the more that social norms will shift in favor of masking.”
Dr. Fischer said he hoped people would move beyond the gaiter controversy and focus on the original goal of the study, which was to find a cheaper alternative to allow for more widespread testing of mask materials.
“Our intent was for this technology to get out there so companies and organizations can test their own masks,” Dr. Fischer said. “A mask doesn’t have to be perfect for it to work.”
This story was originally published at nytimes.com. Read it here.