LOS ANGELES - Mask wearing is becoming the norm amid the pandemic. A growing list of states and cities require individuals to wear face coverings in public, while many major chains and businesses are refusing to let customers into their stores if they aren’t wearing one.
But a recent study by Duke University suggests that one type of mask may not provide a wearer with protection from being infected with COVID-19, and could even increase the risk of spreading the coronavirus to others through respiratory droplets.
A proof-of-concept study published by Duke University researchers in the journal Science Advances measured 14 different types of masks — including two types of N95 masks, several cotton-based masks, a neck fleece and a bandana — and how they transmit respiratory droplets during regular speech.
The researchers determined that an N95 mask without valves, the same type used by many front-line health care workers, was most effective, while several cotton-based masks also provided good coverage.
“On the other hand, bandanas and neck fleeces such as balaclavas didn’t block the droplets much at all,” according to a news release from Duke University.
When speaking about the study’s findings during an Aug. 13 media briefing, co-author Martin Fischer discussed the thin, polyester-spandex mix neck gaiter that researchers tested.
“If you pull that and hold it up to the light, you actually see light through it, it’s very easy to breathe through, which of course then necessarily would mean more breathability, less protection,” Fischer said.
“So with that specific mask, we actually saw what appeared to be an increase in the particle numbers,” he continued. “We attributed that to the mesh, the fabric, actually disbursing some of those droplets, turning bigger droplets into a bunch of little droplets, which of course then increased the number of total droplets.”
Fischer said that what makes this somewhat concerning is how a person can emit big droplets that then fall to the ground, but the smaller droplets have an easier time hovering the air or being carried away.
The researchers said that their study was just a demonstration and that more work is necessary to “investigate variations in masks, speakers, and how people wear them.”
The Duke University researchers are advocating that people wear masks in general to help prevent the spread of COVID-19.
“If everyone wore a mask, we could stop up to 99% of these droplets before they reach someone else,” said co-author Eric Westman, a physician at Duke, in the news release. “In the absence of a vaccine or antiviral medicine, it’s the one proven way to protect others as well as yourself.”