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Canada’s chief public health officer recently released updated recommendations for non-medical masks. Meanwhile, winter is approaching. This has led CBC readers to send us new, more detailed and seasonal questions about wearing masks to prevent the spread of COVID-19. We turned to the experts for answers. (You may also want to check out our previous mask FAQs, including questions like: Does a reusable mask require heat to clean? Can I use a mask instead of a mask? Can I reuse a disposable mask?)
In early November, Canada’s chief public health officer, Dr. Theresa Tam, updated her recommendations on non-medical masks. She now recommends that masks have at least three layers instead of two, and that the third layer be a filter fabric such as non-woven polypropylene. However, she says there’s no need to throw out both layers of the mask.
Health Canada has instructions for making a three-ply mask and says you can find the following non-woven polypropylene materials:
Both N95 and medical masks use non-woven polypropylene material. It shouldn’t lose fiber, says James Scott, professor and director of occupational and environmental health at the University of Toronto’s Dalla Lana School of Public Health.
Even if the mask were to come off, he estimates the allowable fiber exposure would be “higher than I would expect from a mask that comes off.”
He added that N95 masks can be reused up to 10 times without damaging the filter material if they are cleaned with mild hydrogen peroxide between uses. However, he had no idea how durable polypropylene nonwovens would be after repeated washing at home.
At the same time, many other items in our homes are made from synthetic materials, and you were probably still inhaling a lot of polypropylene fibers from the dust around you. A 2016 study by French researchers found that 33% of fibers in indoor air are synthetic, with polypropylene being the main material.
However, there are reports that textile workers exposed to high concentrations of synthetic fibers may cause lung problems.
Apparel labeling laws also apply to non-medical masks, according to the Competition Bureau of Canada. This means that masks sold commercially must have removable labels such as stickers, tags, wraps or permanent labels, including:
Seller’s name and principal place of business (full mailing address) or CA registered identification number.
Canada’s Competition Bureau said the labeling rules apply to businesses and artisans, but not individuals, making masks to give away or donate to friends, family or charities.
However, the company previously acknowledged that because such masks are new to the market, manufacturers may not yet be aware of the rules.
If you believe that a supplier is making false or misleading statements about its products, you can report it to the Bureau using this online form.
Yes, social distancing is still necessary as regular medical and non-medical masks only reduce the number of particles in the nose and mouth. They don’t kill them, says Dr. Anand Kumar, an associate professor of medicine at the University of Manitoba in Winnipeg. (Respirators such as N95s are better at filtering particles.)
While most masks can reduce the spread of particles by about 80 percent, “it’s still 20 percent of the particles that are still spreading. How widespread is this? Nobody really knows,” he told CBC News.
But whether you wear a mask or not, the greater the distance, the greater the protection. According to Kumar, if the distance between you and another person doubles, the number of viral particles reaching you decreases by about eight times. Wearing a mask causes larger, more contagious particles to settle near the infected mask wearer before reaching another person.
Martin Fisher, an assistant professor of chemistry at Duke University in Durham, North Carolina, who has studied how to measure the effectiveness of different masks, said there is no clear answer. This is because the risk depends on many factors, such as how well the mask each person wears blocks particles and the duration of your interaction.
Kumar and other experts noted that methods such as shielding and distancing should be viewed as “multiple layers” of protection that “wear out” together and cannot replace each other.
Australian virologist Ian MacKay uses the analogy of Swiss cheese to illustrate the point: the virus can pass through holes in certain slices, but if there are many layers, it will not be able to pass through the whole cheese.
The colors and partitions of the new version are inspired by @uq_news and by @kat_arden (version 3.0) Exercise strict control over mouse design.
It reorganizes fragments into individual and shared responsibilities (think of this in terms of all fragments, rather than one level that is most important). pic.twitter.com/nNwLWZTWOL
Canada’s top public health official is advising Canadians not to kiss and wear a mask when in close contact with a new partner to protect themselves from the coronavirus.
Colin Furness, an infection control epidemiologist at the University of Toronto, explains that if you are in close proximity (such as kissing), you could accidentally exchange exhaled droplets on both sides of the mask, which could spread the virus.
Given the increase in transmission in many parts of the country, Sumon Chakrabarti, an infectious disease physician at Trillium Health Partners in Mississauga, Ont., said it’s best to follow local public health recommendations, which include minimizing close contact with people other than your own. closest relatives.
Respirators like the N95 do protect the wearer, which is why they are worn by medical personnel treating COVID-19 patients.
A general surgical or non-medical mask whose main purpose is to prevent particles exhaled from the mouth or nose from getting too far away from you.
Research shows that these regular masks are excellent at filtering particles coming out of the wearer’s mouth and nose, as they tend to block larger particles more effectively. This is how they protect others if you become infected.
But yes, there is some evidence that they may also protect the wearer, including a meta-analysis of 172 previous studies published this spring.
Laboratory experiments show they can prevent about 80% of viral particles from entering the nose and mouth, which could reduce the severity of COVID-19 infection by reducing the dose if infected.
Dr Susie Hota, medical director, said: “When we pooled all the data, we found that masks can generally help reduce the risk of face-to-face contact outside healthcare settings and even within the wider community. Broadcast”. Infection Prevention and Control, University Health Network, Toronto.
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Post time: Dec-03-2023