As of July 18th 2020, masks are mandatory in interior public spaces in Quebec, sparking a debate around the true benefits versus discomforts of wearing a mask: some people oppose it. Statements made in opposition have left many confused. Dr. Maxime Cormier, a respirologist at the Montreal Chest Institute of the McGill University Health Centre (MUHC), with expertise in asthma and one of the key doctors who launched the first COVID ward at the Glen site, weighed in on the conversation and provides a bit of clarity regarding some of the myths about wearing masks.

Is it true that masks make it difficult to breathe and those with asthma should not wear a mask?

There is no medical reason, from a respiratory standpoint, that you shouldn’t wear a mask. The only reasons a mask could be problematic is in the case of severe facial burns or deformations, or some forms of post-traumatic stress disorder (PTSD). Asthma patients, with symptoms ranging from mild to severe, even those who depend on their inhalers, can breathe comfortably while wearing a mask.  That said, there are some patients whose respiratory symptoms worsen when they wear a mask, not due to their asthma getting worse but to mask wearing anxiety. The anxiety stems from the sensation of airflow restriction associated with partially covering the face. “This is a very common reaction seen in patients with asthma,” says Dr. Cormier, “and it can sometimes be hard to differentiate between asthma symptoms and hyperventilation syndrome or dysfunctional breathing.”

Patients with dysfunctional breathing syndromes will likely have symptoms triggered by wearing a mask, but it’s not dangerous and they can be calmed by breathing exercises.

Is it true that COVID-19 particles are so small that they can seep through the fabric of the masks, rendering the masks useless?

We have learned that transmission of the virus can happen 1 to 2 days before any symptoms can appear, and can be transmitted by people who are symptomatic or asymptomatic. However, the virus needs to get into the air inside a respiratory droplet in order to be transmitted, which a mask can stop. That said, Dr. Cormier emphasizes that the primary reason why people are encouraged to wear masks is to protect others from catching the virus and less to protect themselves from contracting it.  But if others around you are wearing masks then you are protected, and vice-versa.

What about the World Health Organization (WHO) reports now stating that the virus could possibly be airborne?

“There is new evidence that suggests transmission can occur in settings where people potentially breathe out more particles close to others, like when someone is singing or talking loudly in a restaurant or a bar, or even choir practice,” stated Dr. Cormier, “In these settings, the virus could be airborne, as people are most likely to be in close proximity to one another – although this new evidence is still being debated.”

Since the main way to catch COVID-19 is by touching a contaminated surface and then touching your mouth or your eye, inhaling respiratory droplets is an extremely small part of the mechanical transmission.

Is it true that while wearing a mask, you inhale the carbon dioxide that you’ve exhaled, which can cause you to become very ill and could be potentially fatal?

The actual concentration of CO2 levels when you exhale is quite low. When we breathe, some of our airflow stops at the trachea and bronchiole, and doesn’t all participate in the gas exchange which turns it into CO2. We breathe in about 500 ml of air at a time, and the amount of CO2 that we breathe back in from our previous exhaled breaths is so very small that it poses absolutely no danger. It in no way affects our CO2 or oxygen levels. A good example to take into account is that surgeons and nurses use tighter fitting masks for very long periods every day and there is absolutely no evidence that this has any bad health effects other than “feeling hot” or “uncomfortable”.

Is it true that if ever you were infected with COVID, and you breathed into a mask, the COVID particles that you breathe back will worsen your infection and increase your risks of dying?

This is completely false. If you have COVID-19, there are already some viral particles inside your infected cells, so the small amount of viral particles that could have stuck inside your mask is insignificant compared to the levels that are already inside your lungs and airways. Your body will clear the virus through its immune system, not by “expelling” it into the air, so wearing a mask will not impair your healing process from COVID-19. Coughing out the virus will not make you heal any faster either: if anything, it could infect others around you. Therefore, wearing a mask, even if you have COVID, is the best option.

Is it true that cloth masks are the worst kind and hospital masks have to be changed every 20 minutes?

Any type of mask that blocks respiratory droplets containing viral particles works in preventing the spread of the virus. Although different types of masks may have better air filtration properties (such as an N95) or levels of comfort, the point is to have a mask that will act as a barrier, blocking the spread of respiratory droplets. Any face-covering (cloth or paper) will do the trick. Indeed, a surgical mask can get wet more quickly which could make it easier for droplets to detach from the outer mask lining, but it is better than wearing no mask at all. We still recommend that a paper surgical mask be changed if it is visibly wet or soiled.

Is it true that there has been an increase in Legionnaire’s disease associated with wearing dirty masks?

There is absolutely no evidence that wearing a mask increases your risk of getting Legionnaire’s disease. Legionnaire’s disease (also called Legionella pneumonia) is a type of lung infection that is acquired when you inhale droplets containing the bacteria causing the disease, in this case Legionella pneumophila. The bacteria is usually found in contaminated stagnant water such as in hot water tanks, cooling towers, or large air conditioning systems. It is in no way associated with masks or face-coverings.

It is unclear if the mask is 100% effective in stopping transmission, but Dr. Cormier believes it assuredly decreases the risks exponentially. If everyone respects the two metres of physical distancing, practices good hygiene and wears a mask, the chances of contraction become minimal and community spread of the COVID-19 virus can decrease.


To learn more about wearing a mask in public settings, click here