CSU experts explain mask recommendations, which masks offer highest protection

With the omicron variant of COVID-19 spreading more rapidly than previous variants, experts are advising people to ditch the cloth masks and find KN95s or N95s to protect themselves and others from the virus. 

But why are we getting this advice now, and what is the difference between the various types of masks? 

John Volckens and Christian L’Orange, professors of mechanical engineering at Colorado State University, have been testing the efficacy of masks since March 2020. Volckens and L’Orange said it’s always been clear that N95s are the ideal mask for protection but that earlier in the pandemic there wasn’t the capacity to produce enough for everyone to have so they were saved for people in the medical field and frontline workers. 

But because omicron is so highly transmissible, now is a time where more people need higher protection. And N95s and KN95s are more easily accessible, too. 

The general public can find these masks in stores and online because supply has finally caught up to the global demand, and Volckens recommended that everyone should be in one. To explain why an N95 is superior, he said it helps to think about masks as safety features in a car.

"Any mask might be like a seatbelt," Volckens said. "But an N95 is a car with front airbags, side impact airbags, early warning detection, sensors for proximities. It is much much much better ... all those extra layers of safety is really what an N95 gives you." 

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How cloth, surgical, KN95 and N95 masks compare

When looking for an effective mask, experts say two important factors are a strong fit and good filtration.

L’Orange described how the different types of masks — from cloth to medical grade — when worn correctly build on features from less effective ones. Cloth masks are the least effective because of weak filtration and loose fit. KN95 masks are more effective in filtration but not great for fit, and N95 masks have strong filtration and strong fit.

However, they both said a cloth mask is better than no mask if it’s the only option.

Surgical masks are another good option because of strong filtration, but the loose fit reduces efficacy. If it was possible for them to be as tight to one's face as an N95 or KN95, they'd likely be equally effective, Volckens said. 

To test the efficacy of masks, L’Orange and Volckens secure the masks to a platform and place it in a chamber where aerosols are introduced. They then test the amount of aerosols in the chamber and behind the mask to see how many get through.

In order to be certified, KN95 and N95 masks must prevent 95% of aerosols from getting through, though Volckens said many are actually 99.9% effective. 

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How to test your mask at home

If you don’t have thousands of dollars worth of equipment to test your mask’s efficacy, there are other ways. 

Volckens recommends folks at home do an “eye blink test.” Wearing your mask, he said to take a big breath out. If you blink, air is able to escape through the mask, meaning its fit isn’t ideal and it’s not protecting you as best it can. If you don’t blink, the mask is doing its job with a strong fit and is highly effective. 

Another way of telling if your mask is effective and has strong fit is to run your fingers around the outside of the mask. If there is any place where it's not touching your face, air can get in and the mask is not as effective as it could be, L'Orange said. 

There are a number of counterfeit KN95 and N95 masks on the market now that they're more widely available, and Volckens' advice to avoid these was to buy directly from an industrial safety supply company or from projectn95.org. 

Bonus content at Coloradoan.com

Find this story at Coloradoan.com to view videos on how John Volckens and Christian L’Orange test masks.

Editor's note: A previous version of this story misspelled Volcken's last name and has been updated with the correct spelling. 

Molly Bohannon covers education for the Coloradoan. Follow her on Twitter @molboha or contact her at mbohannon@coloradoan.com. Support her work and that of other Coloradoan journalists by purchasing a digital subscription today.