'Fitting hacks' for KN95 face masks may make them less comfortable, study finds

Photo (c) Grace Cary - Getty Images

Experts say masks need to fit tight against the face

As the COVID-19 pandemic continues on and mask mandates are still in effect, it’s been difficult for consumers to find masks that fit properly and also keep them protected from infection. As a result, many consumers have tried different fitting hacks with their face masks

In a new study conducted by researchers from the University of Cambridge, the team put these fitting hacks to the test. Ultimately, they learned that while many of them are effective at getting consumers a better fit, they may lack comfort. 

“In order to provide the advertised protection, a mask needs to be fit tightly to the face – there should be no visible gaps around the edge of the mask,” said researcher Eugenia O’Kelly. “We’ve seen lots of anecdotal evidence of people hacking their masks to better fit the shape of their face, but we wanted to validate whether any of these hacks actually work, as very little research has been done in this area.”  

Finding the right mask fit

For the study, the researchers put six fitting hacks to the test on four participants wearing KN95 masks and surgical masks: knotting the ear loops, sealing the edges with tape, pressing the mask to the face with tights, binding the mask to the face with gauze, using rubber bands to create a brace, stuffing the gaps with first aid gauze. The team also conducted one trial with no adjustments to the mask. Each of the fitting hacks were subjected to two assessments: the first involved spraying a flavored substance and seeing if the participants tasted it while wearing the mask; the second measured the level of particles both inside and outside the mask. 

Ultimately, the researchers learned that comfort was the biggest detriment to these different mask-fitting hacks. From a safety perspective, the tights proved to have the biggest effect on improving the fit of the mask, for both the KN95 mask and the surgical mask. However, they also created the tightest fit, which, while protective, proved to be uncomfortable for the participants. 

“For most of the hacks, comfort was a big issue,” O’Kelly said. “The rubber bands, for example, tended to put painful pressure on the ears and face, to the point where they hindered circulation to the ears. However, using an effective but uncomfortable hack may make good sense in some high-risk situations, where the discomfort is worth it for the added protection, but it would be harder to wear these hacks day in and day out.” 

The study showed that sealing the edges of the mask with cloth tape was effective at improving the overall fit of the mask; however, the participants expressed extreme discomfort when having to remove the tape. While the other interventions were mildly effective at improving the fit, none did so as well as using the tights or the cloth tape. 

The researchers explained that many face mask fitting issues come from the fact that everyone has a different face shape, but masks are developed with few variations. Moving forward, they hope these findings are used to improve the development of face masks. 

“We hope that these results can be used in the design of future masks in order to ensure that they are as tight to the face as possible, for as many wearers as possible, without making them uncomfortable,” said O’Kelly. 

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