But what about airflow — and just how airtight are they?
“For any mask or fancy filter, one thing we need to keep in mind is how well they fit, tightly, to the face,” said Chenyu Sun, an internist at Saint Joseph Hospital in Chicago who recently co-authored a study on face mask efficacy.
Dr. Sun said health care workers often get specially fitted for N95 masks, and the one-size-fits-all approach of retailers is troubling. So is the lack of guidance for proper use.
“Inside out, upside down, probably even less people know how to take masks off properly without contamination. This also applies to these devices,” said Dr. Sun, who added that sporting doomsday gear may have unintended psychological consequences. “Will the general public really accept these? Now, even for regular masks, there is a lot of debate.”
“People double-take, but I think Canada is very polite so nobody stares too long,” said Mr. Al-Qasi, who wears the BioVyzr around downtown Toronto, where the company is based.
Raina MacIntyre, the head of the Kirby Institute’s biosecurity research program at the University of New South Wales and the lead author on a recent face mask review, warns that if these masks don’t “provide a perfect seal on all contact surfaces, unfiltered air will flow preferentially through the gaps. HEPA filters are good for filtering pathogens, but these devices need to be tested for fit and filtration.”
She added: “The reason for needing a perfect seal is to force the air through the filter.”
Real efficacy, she said, means approval by the F.D.A. and the National Institute for Occupational Safety and Health, the agency that regulates this form of powered air respirator. “The virus is present in aerosols, so such a device will not be protective.”