MINNEAPOLIS (WCCO) – A year into the pandemic, a simple solution remains one of our best weapons against COVID-19. The CDC says wearing a mask can help slow the spread of the virus.

But how can you be sure yours offers the best protection? WCCO shares a simple test from the Minnesota scientists in search of the perfect fit.

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When the pandemic hit, Neil Carlson answered the call from the state’s critical care supplies work group.

Carlson, a public health specialist in the University of Minnesota’s Environmental Health and Safety department, used a machine to test respirators, and surgical and cloth masks by himself, because of COVID concerns. He checked hundreds to ensure they passed his test before the state bought, and distributed them, to the front lines.

“They said ‘hey, do these work at all,’ and so they would give me two to three of each one, and I would run it through a test,” Carlson said

The machine Carlson uses measures the particles outside and particles inside.

“The fit is really important, because if you have any space or gap in the mask, it essentially negates everything you’re doing with filtration,” Carlson said. “Some of them fit very well, other ones were just really poor. They didn’t do the critical work.”

That work has slowed as the state found trustworthy suppliers. And Carlson shifted his focus to graduate students, and to help Alison Cloet and Minji Yu formulate a superior facial fit.

“What we’re kind of investigating is if adjustability is a factor that can improve mask fits and efficiency,” Cloet said.

The focus is on health care workers, looking at fit factor data, and their facial dimensions, looking at how cheek bones, noses and chins impact the fit of the mask throughout the day.

“My specialty is in the face scanning,” Yu said.

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The goal is to one-day give manufacturers data to develop a size system.

“So we’re just hoping to really research how to stabilize fit, and guarantee effectiveness of the respirator,” Cloet said.

There are ways to test the fit of your mask at home. One is the tissue test, you put it out about an arms-length away, blow as hard as you can. If the tissue doesn’t move, it’s passed the test.

Carlson says if you have glasses and they fog up with the mask on, it means gaps are allowing particles to flow in and out.

“You’re not protecting the other person, and you’re not protecting yourself very well,” Carlson said.

The same applies to facial hair.

“The facial hair pushes the mask far enough away from the face that it allows the small particles to come right in,” Carlson said.

And he says when you’re breathing in, the mask should collapse a little bit.

Carlson says an N-95 mask has a fit factor of 100. The common surgical blue mask is about a five. That’s good he says, but with the new variants, putting a cloth mask over it is even better. Doubling up can bring the fit factor to 20. Carlson says any mask is better than no mask.

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To see CDC’s recommendations for improving mask-wearing, click here.

Jennifer Mayerle