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For her master’s thesis, McMaster University student Fatima Sheikh spent time at Hamilton Health Sciences, looking at N95 mask standards through an equity, diversity and inclusion lens.
January 20, 2023

The best-fitting N95 mask for everyone

Due to the ongoing threat of COVID-19 infection, masks are required for everyone at all Hamilton Health Sciences (HHS)  hospital sites. And for health-care professionals working in higher-risk settings, a special type of mask called an N95 respirator is the standard to protect wearers from inhaling pathogens like the COVID virus.

The first N95 masks designed in the 1950s and 60s were for industrial workers, not health-care workers, says Fatima Sheikh, who conducted a study at HHS in 2021 as a master’s student, and is now working on her PhD in health research methodology. These industrial workers were mostly white men of European heritage, she adds.

“Ms. Sheikh’s research is groundbreaking in starting to unpack the systemic biases built into our health-care system, which impact our patients and staff.” — Dr. Sarah Khan.

Now that N95 masks are used so extensively in health care, Sheikh wanted to see how mask standards can be improved for a larger variety of facial shapes and sizes including women and people from many different ethnic backgrounds.

Finding the best fit

“A key feature of an N95 mask is that it’s sealed to a person’s face,” says Sheikh. “So it’s possible that if you’re a woman, or come from a different ethnic background, your mask may not be designed as well as it could.”

There are other considerations too, adds Sheikh. “For example, I wear a scarf and some health-care workers also wear turbans for religious reasons. With head coverings, the mask has a tendency to move around which can affect comfort and performance.”

Dr. Sarah Khan, pediatric infectious diseases specialist and associate medical director for infection prevention and control at HHS, was an external examiner for Sheikh’s master’s thesis.

Dr. Sarah Khan, an external examiner for Fatima Sheikh’s master’s thesis.

“Ms. Sheikh’s research is groundbreaking in starting to unpack the systemic biases built into our health-care system, which impact our patients and staff,” says Khan. “As our patient and health-care worker population continues to diversify we need to review the standards we use to ensure they match the needs of our new reality.”

Using the gold standard at HHS

Canadian hospitals use respirator masks designated as N95 by the U.S. National Institute of Occupational Safety and Health (NIOSH). These NIOSH-certified masks are the gold standard and fit most faces.

At HHS, staff and doctors requiring N95 masks are fit-tested according to standards set by the Canadian Standards Association. Then they’re assigned a mask model that will work best for them out of seven approved masks.

“These are excellent masks.” — Steve Jamieson, HHS safety manager

“I can assure our staff and doctors that if they’ve been fit-tested, trained, and use the N95 according to the standards, their N95 mask is providing the right level of protection,” says HHS safety manager Steve Jamieson.

“These are excellent masks. We have only a very small number of workers across the corporation that are not able to be successfully fitted to one of our available models of N95, in which case we look at different options to ensure the safety of the worker.”

The Canadian Standards Association reviews and updates its mask standards every five to 10 years, with the last update in 2018.

Studying facial measurements at fit-testing

Sheikh spent several months helping at N95 mask-fitting clinics for health-care workers at HHS’ Hamilton General Hospital, McMaster University Medical Centre and Juravinski Hospital. Along with this work, she conducted research on whether existing standard masks offered the same fit, comfort and breathability for women and people of diverse backgrounds.

These mandatory mask-fitting clinics were offered long before COVID, but became extremely busy at the beginning of the pandemic and have stayed busy as more and more health-care workers required the extra protection of an N95 mask.

In January 2021, when Sheikh started volunteering, health-care workers were lining up for an hour or more for clinics.

“Trying to conduct research during the pandemic was beyond challenging,” says Sheikh, whose study took a back seat for several weeks while she helped HHS safety fit-tester Bonnie Peacock move people through clinics as efficiently as possible.

Fatima Sheikh demonstrates taking facial measurements.

Sheikh’s study required participants to spend extra time with her after their mask fitting for facial measurements and a survey. While many health-care workers expressed support for the study, most were too busy due to pandemic pressures to participate.

“They wanted their mask fitting done as quickly as possible so that they could get back to work,” says Sheikh.

Any HHS health-care worker was welcome to take part, though Sheikh screened for participants from diverse backgrounds, as well as those who identified as female. Of the 653 people who attended clinics while Sheikh was volunteering, 36 volunteered for the study. It’s a small number, but the information collected is still valuable, says Sheikh, who has presented her findings at several conferences and is in the process of publishing her work in a scientific paper.

For the health-care workers who participated, the study included a survey covering fit, comfort, and breathability as well as physical health such as any rashes to the face, and mental health including stress from concerns like supply shortages in the earlier days of the pandemic.

Sparking innovation and creativity

Sheikh used the current standard NIOSH grid system to measure participants’ faces, cheekbone to cheekbone and from the bridge of the nose to under the chin, and found that 75 percent of the 36 participants’ faces did not fit the NIOSH grid.

Bonnie Peacock, HHS safety fit tester

That doesn’t mean their masks couldn’t be fitted properly, says fit-tester Peacock, who ensures people have the best size and shape of mask available, and that they are properly sealed and comfortable.

Rotating fit-testing clinics take place across HHS, so health-care workers can drop by at their convenience. Every HHS health-care worker using a respirator mask must be fit tested every two years at the clinic, or sooner if there’s a change to the size or shape of their face due to, for example, a change in their weight.

Next steps for Sheikh include sharing the study findings with organizations responsible for national design standards, to help ensure that future designs reflect the diversity of Canadian health-care workers.

In some ways the pandemic has allowed for innovation and creativity, says Khan. “Ms. Sheikh’s project hopefully will spark future creative solutions to address this issue.”