Masks: Everything you need to know but might be too afraid to ask

The information in this article was current at the time of publishing, but guidelines and advice can change quickly. Check with your local public health unit for the most-current guidance, and find the latest COVID-19 news on our website.

We're answering your questions about the pandemic. Send yours toCOVID@cbc.ca, and we'll answer as many as we can.We publish a selection of answers onlineand also put some questions to the experts duringThe Nationaland on CBC News Network. So far, we've received more than 41,000 emails from all corners of the country.

We've received more than 1,000 questions about masks from Canadians, and some inquiries show that many of you are just straight-up confused about wearing them.

With the country reopening, and Canadian public health officials now recommending the use of masks in public, we took your most common orcurious questions to the experts.

Here's what you wanted to know about masks.

What's the point of wearing a non-medical mask?

Chief Public Health Officer Theresa Tam says masks can "add a layer of protection" in situations where physical distancing is impossible, but that protection is only for the people around you.

When you breathe, cough, sneeze or laugh, droplets are expelled fromyour mouth and nose.

WATCH | Dr. Theresa Tam explains her latest recommendation on mask use:

Dr. Tam explains new recommendation on masks

4 years ago

Duration 2:27

Dr. Theresa Tam, Canada's chief public health officer, is now recommending that Canadians wear masks in public as an "added layer of protection" whenever physical distancing is not possible.

"If you wear a mask, you may notice after a while it's getting damp, so the moisture in your breath is staying behind," said Colin Furness, an infection control epidemiologist and assistant professor at the University of Toronto.

The hope is that the mask stops some of your droplets from reaching the air and could stopthem from contaminating surfaces and people.

But Furness cautions that there are no comprehensive studies on the efficacy of cloth masks, and they "aren't a guarantee of anything."

If cloth masks can stop stuff from getting out, can they stop stuff from getting in?

"Maybe a little bit. Maybe not," said Dr. Isaac Bogoch, an infectious disease specialist and researcher based at the Toronto General Hospital.

"We don't really know," he said. "It might slightly reduce one's risk [of exposure], but I can't look you in the eye and tell you if it does and by how much."

Furness agreed. He saidmasks areprobably helping "a bit but the research is really thin," especially considering all the different kinds of materials that people are using to make masks.

"There is a temptation and a risk to feel safer when you wear your mask," Furness said. "But you're not. There is no substitute for physical distancing."

Is there any material that's better or worse for a cloth mask?

According to Health Canada, non-medical face masks or face coverings should be made of at least two layers of tightly woven material fabric, such as cotton or linen.

Knit materials such as the kind used in most T-shirts are stretchable, and small holes open in the knit. That's why woven fabrics are considered more effective.

The masksshould allow for easy breathing;be comfortableand not require frequent adjustment;and be large enough to completely and comfortably cover the nose and mouth without gaping, according to Health Canada.

Canada's deputy health minister, Howard Njoo, said that a simple way to tell if your mask is thick enough is by using what he called the "window test."

"If you can hold the material of the mask to a window hopefully, with the sunshine outside and it's not translucent and pretty opaque, it will at least do the job in a general sense," he said.

A 2013 studyin the journal Disaster Medicine and Public Health Preparednessfound tea towels had the best filtration efficiency. The same study suggested cotton works better than silk or linen.

WATCH | Can cloth masks protect you from COVID-19? Two doctors weigh in:

COVID-19: Should people wear homemade masks when they go outside?

4 years ago

Duration 3:30

Doctors answer your questions about the coronavirus, including whether people should be wearing homemade or cloth masks when they are outside.

A more recent study by researchers in the United States found a layer of tightly woven cotton with two layers of polyester-based chiffon, cotton-polyester flannel or silk worked well.

It is "hard to comment on the ability of [cloth] masks to filter," because unlike medical masks, homemade masks don't require any standards approval, saidJohn Granton, an intensive care doctor at the Toronto General Hospital and head of the respirology divisionat Mount Sinai Hospital and the University Health Network.

Should I use a filter in my cloth mask?

Health Canadasays adding a filter to your homemade cloth mask, "such as a paper towel or disposable coffee filter," can provide an "increased benefit."

But Njoo said that people should be very cautious in making filters from materials they find in their homes.

"Certain materials and filters [may be] impregnated with chemicals," Njoo said. "That could be a risk to the wearer because they could be inhaling toxic substances."

He said the general public shouldn't get "too complicated" with filters for now. Innovators and scientists will likely come up with different recommendations, he said.

Steve Theriault, a virologist specializing in infectious disease, said that just because something in your house is called a "filter," it doesn't mean it will filter outthe virus.

"I understand why people are talking about coffee filters because they see it filters their coffee, right?"said Theriault, CEO and chief science officer of Cytophage, a Winnipeg-based biotech company.

"But [with] a virus, there's millions and millions of them on the tip of a pen."

How effective are alternatives to masks, such as bandanas, balaclavas and neck gaiters?

While these are usually allowed as face coverings, none of them work very well to block respiratory droplets, and neck gaiters or neck fleeces may actually be worse than wearing no face covering at all, according to a recent study in Science Advances comparing different kinds of masks.

That study found neck gaiters tended to break large droplets into smaller ones, creating more particles that stayed airborne longer and potentially increasing transmission.

I have facial hair. Do I have to shave to make my mask effective?

If you have a fitted medical mask, such as an N95, having a seal that isn't inhibited by facial hair is very important.

But a cloth mask, Furness said, doesn't create that same seal so whether or not you have facial hair doesn't actually matter.

WATCH | WHO guidance onthe correct way to wear a mask:

COVID-19: What you need to know before wearing a mask

4 years ago

Duration 2:30

Dr. Samir Gupta provides crucial information about wearing a mask during the COVID-19 pandemic and what to think about before putting one on.

"If you have a beard, it's not going to matter either way. No one's pretending there's a seal there," he said.

Bogoch said the goal with cloth masks is to reducethe amount of virus shedding frompeopleto the area around them.

"Beard versus no beard, I wouldn't sweat it," said Bogoch.

What if I have to sneeze or cough when I'm wearing my mask?

In short: Do it into your mask and into the crook of your arm. The mask's whole purpose is to try to stop some of the droplets spewing from your mouth and nose.

After you've sneezed or coughed into your mask, you should "swap it for another one," said Furness.

You could also use a tissue or Kleenex underneath your mask, he said. Don't forget to wash or sanitize your hands afterward.

WATCH | Mask mistakes you might be making, and how to avoid them:

Are you making these face mask mistakes?

4 years ago

Duration 3:55

A face mask is meant to limit the spread of COVID-19. But if it slips below your nose, hovers around your chin, or you touch the outside with your hands, medical experts say that might be riskier than not wearing one at all.

So, why is it that people are hesitant to cough or sneeze into their mask?

People who take their mask off to sneeze or cough are usually people who think the mask is there to protect themselves, Furness said. It's not.

How do I stop my glasses from fogging up when I'm wearing a mask?

If your glasses are misting or fogging up, it's a sign your mask might not be fitting right.

When warm breath escapes from the top of the mask and lands on your glasses, it creates condensation or fog.

"Creating a good seal above the bridge of your nose is key," said Dr. Jason Cyr of Humber River Hospital in Toronto.

"You can accomplish this either by having a comfortable mask that moulds to the bridge of your nose well or by putting a piece of tape to hold it in place," he said.

"You can also apply some form of anti-fog to your lenses."

You could also try this trick recommended by British surgeons. A paper published in the medical journal Annals of the Royal College of Surgeons of England says washing your glasses with soap and water and letting them air dry can prevent lens fogginess while wearing a mask.

Is there any danger in wearing a mask?

Actually, there can be.

If people are wearing masks for extended periods of time without properly cleaning them, Furness said, a bacterial biofilm can build up on the outside layer of your mask.

"If 30 million Canadians are wearing a cloth mask all day long, you'll see a noticeable spike in bacterial lung infections in a month or so," he said. "Especially because many people wearing them are often immunocompromised.

"Think about it: Our bodies are not designed to have a dirty cloth in front of our mouth all day."

Furness said you should still wash your mask in your washing machine after each use. He also recommends boiling it once in a while to killbacteria.

The big risk with face masks is self-contamination that is, if you adjust your mask with dirty hands.

The experts with whom we spokesaid good hand hygiene and not touching your face is key when wearing masks, especially when taking them on and off.

Should we be wearing goggles or face shields, too?

While it is possible to get COVID-19 through one's eyes, experts say you can probablyskip the goggles or face shields for normal daily activities.

"For the average person, [wearing] a mask is reasonable," said Zain Chagla, an infectious disease physician at St. Joseph's Healthcare Hamilton and an associate professor of medicine at McMaster University.

He says it would be "very difficult" for droplets to infect a person's eyes during casual exposure in public, especially if they're maintaining physical distance.

When eye contamination does happen, Chagla says, it's more likely because someone touched their eyes with their hands.

"Realistically, hand hygiene is the biggest part of preventing ocular transmission," he said.

Mark Downing, an infectious disease physician at St. Joseph's Health Centre, said that the risk of eye contamination in public is "very low." He says wearing a mask while physical distancing is "far more useful" than goggles or face shields to protect yourself and others around you.

He warns that face shields are not a replacement for masks, because face shields have gaps where droplet particles can enter and exit.

And, of course, health workers are highly trained to use personal protective equipment so they don't contaminate themselves in the process.