Importance of high-quality masks glimpsed in droplet experiment

Published: Dec. 24, 2021 at 6:46 AM MST
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PALM BEACH COUNTY, Fla. (CNN) - Holiday travel is reaching pre-pandemic levels at the same time infections are peaking from the omicron variant.

The TSA is anticipating 20 million people will fly between now and Jan. 3.

The Centers for Disease Control and Prevention said travelers can reduce their risk by being fully vaccinated, boosted and wearing the proper mask.

Masking and social distancing are more important than ever when traveling.

Bottom line: Experts suggest grabbing a KN95 or N95 mask if available before hitting the road, and keep your distance from your fellow passengers.

Inside lab at Florida Atlantic University, two engineering professors measured how coronavirus can spread through the power of a cough.

They filled a mannequin’s mouth with a mix of glycerin and water. Next, they used a pump to force it to cough, then waited to see how far the droplets travel.

The droplets filled the air, made visible with a green laser light.

Holiday travelers take note: The droplets expelled advanced a distance of 3 feet almost immediately.

Within five seconds the droplets had traveled 6 feet, then 9 feet in just about 10 seconds.

Remember, 9 feet is 3 feet beyond the recommended social distancing guidelines.

“It’s already reaching roughly 9 feet now, it’s still moving farther, slowly,” said Sid Verma, associate professor of ocean and mechanical engineering at Florida Atlantic.

The fog of droplets lingered in the air and can do so, the professor said, for several minutes.

It took about 30 to 40 seconds to float another three feet.

“It is getting closer to 12 feet now,” Verma said.

Over and over again, the simulated droplets blew past the 6-foot mark, often doubling that distance.

In fact, while the CDC says it is less likely, infections have been transmitted to people who were more than 6 feet away, even in people who passed through the area after the infectious person had already left.

It’s all part of why the CDC still insists on keeping your distance from others while traveling and wear a high-quality mask.

The professors tested masks, too, and it’s easy to see why some experts say cloth masks and anything that’s just a single layer offer so little protection.

First, they tested a single-layer gaiter.

“This gaiter is a bit surprising because it seems to let everything through without any stoppage,” said Manhar Dhanak, chairman of ocean and mechanical engineering at Florida Atlantic.

Next up, a single layer bandana, made of 100-percent cotton, performed a little better than the gaiter.

“What you see there is this quilted cotton one-layer mask performs a little better than the gaiter,” Dhanak said. “You still get some leakage coming through. It filters some of the droplets, but some escape through with the single layer. They don’t go very far, probably about 6 inches from the face when you’re just talking.”

A double-layer mask, made of quilted cotton, also spread respiratory droplets when the mannequin talked and coughed, but not as badly as the gaiter and the bandana.

“It doesn’t go very far, probably about 2, 3 inches from the face, so, significantly better than the other masks,” Dhanak said.

What about those blue surgical masks so many people are wearing on airplanes and in airports?

They did well, but there’s room for improvement.

When the mannequin “coughed,” not much went through the mask, but quite a bit leaked out the top.

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