Save the Gaiters! – The New York Times

Save the Gaiters! - The New York Times

“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. Over all, 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.”

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