With several new COVID-19 strains circulating, some experts are debating if the public should be wearing N95 respirators, too.
Taher Saif, mechanical science and engineering professor at the University of Illinois, studied the effectiveness of certain fabrics this past year when those fabrics are used in face masks.
And Saif has strong opinions on the concept of N95 respirators for all.
“It’s a terrible idea,” Saif said.
Saif said a number of companies are making N95 and KN95 masks and making them available to the public (“You can buy them on Amazon” he said), but he questioned the quality control involved in widespread distribution.
“They probably are very good at blocking the droplets,” Saif said. “But they are very bad for breathing purposes.”
In fact, according to the Centers for Disease Control and Prevention, “People with chronic respiratory, cardiac or other medical conditions that make breathing difficult should check with their health care provider before using an N95 respirator because the N95 respirator can make it more difficult for the wearer to breathe.”
According to the CDC, workers “must pass a fit test to confirm a proper seal before using a respirator in the workplace.”
N95 respirators are not the same as a regular surgical face mask. The CDC has a chart here showing the differences.
Saif compared wearing a mask that hinders breathing with jumping onto a boat with a hole in it.
“Even you cannot breathe through your mask,” Saif said. “You will have to find a way out.”
One of two things will happen, he said. Either the wearer will loosen the mask, lessening its effectiveness, or the wearer will start breathing hard, which will force more air in and out, also lessening the face mask’s effectiveness, he said.
Saif isn’t just referring to N95 respirator use by the general public. He’s talking about any cloth or surgical mask, or any combination of the two, since some people are doubling up on them, that makes it difficult for the wearer to breathe.
“But if there’s too much breathability, that’s not good either,” Saif said. “It’s like wearing a mask with a big hole in it.”
For face masks to work as they should, they must seal the face. Medical masks don’t seal the face and wearing two medical masks simply creates larger gaps, Saif said.
“Once the leaks are created, it’s anybody’s game,” Saif said. “How can we convince people of this elementary fact? I don’t know.”
Instead, Saif recommends a two-layer face mask made from common T-shirt cloth. Face masks made from T-shirt cloth are more breathable than medical masks even when three layers are worn, he said. They also are very efficient at blocking particles, he added.
Plus, T-shirt material is comfortable to wear and very inexpensive, putting its availability within reach of the general public, he said.
So the U of I measured how well different fabrics blocked droplets. Fabrics the researchers tested included blends of cotton, polyester and silk, comparing them with medical and surgical masks.
Saif said that one layer blocked about 50% of the droplets and that two layers blocked 95% of the droplets. But the droplets that reach the second layer also don’t have the same velocity that the droplets the first layer caught, either.
“They can’t get through because they don’t have much velocity left,” Saif said. “So the second layer becomes highly efficient.”
But just because 5% to 10% of the droplets are left doesn’t automatically mean the face mask failed. Saif feels the remaining droplets may not have enough viral load to cause infection.
Another disadvantage of disposable masks is that they’re terrible for the environment. Saif said 3 million masks currently are being disposed of every minute and that they are clogging up oceans and drainage systems.
Now consider how many millions of face masks will be thrown away every 24 hours – and by the end of the year, he said.
What will happen to the environment, he asked.
“So it’s our call,” he said. “If we use a cloth mask, we can use it over and over again. We can make two or three for ourselves and wash them every day and use them the next day for months. Once we dispose of them, they’re biodegradable.”
In an updated post on Dec. 18, the CDC also recommended, tight-fitting, double-layer masks made from tightly woven, breathable materials such as cotton or cotton blends, and referred to the U of I study on its site.
For details of the U of I study, including two videos of the droplet tests of one and two-layer T-shirt fabrics, visit news.illinois.edu/view/6367/808377.