Cloth masks do not trap CO2, say health officials

OKEECHOBEE — People all over the world have often covered their mouths and noses with cloth for various reasons, and without ill effects. Cowboys used bandannas to make it easier to breathe on a dusty trail (not to mention rob banks and trains in old movies). Fishermen use neck gaiters pulled up over their noses to protect them from sun and spray. People who live in cold climates wrap their heads with woolen scarves to stay warm. Desert dwellers use cloth wrappings to protect their faces from sand and wind.

And yet, posts made on social media — and repeated at public hearings about face mask ordinances — allege that face mask are health hazards that trap exhaled carbon dioxide. “Masks are killing people,” claimed an angry Palm Beach County woman at the June 28 public hearing on the mask ordinance.

“In the real world, the average mask user without pre-existing respiratory illness has nothing to worry about — except COVID-19,” wrote Kevin Hunt, of Hartford Health Care.

“Only an airtight mask could possibly cause any breathing difficulty,” Hunt explained. “That eliminates cloth masks, the preferred personal protective equipment in public. It actually eliminates N95 respirators, too, usually reserved for health care professionals. They fit tighter than a cloth mask but still not tight enough on the face to kill. Surgeons wear even more substantial face coverings all day without endangering their health.”

An article on Healthline.com states it clearly: “No, face masks can’t cause CO2 poisoning.”

“There is no risk of hypercapnia (CO2 retention) in healthy adults who use face coverings, including medical and cloth face masks, as well as N95s,” Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital, New York, told Healthline. “Carbon dioxide molecules freely diffuse through the masks, allowing normal gas exchange while breathing.”


In response to numerous posts on social media by people who complained about face masks, Dr. Megan Hall, a pediatrician, conducted an experiment and posted the results on Facebook.

“I have seen numerous posts and heard people complain they ‘can’t breathe with a mask on’ or they won’t wear one because ‘oxygen levels drop dramatically while wearing a mask.’ Also, a mask doesn’t protect you from breathing in the virus’ but in the same sentence argue they won’t wear one because they are ‘rebreathing their exhaled carbon dioxide.’ I’m not sure how one can even make sense of this theory; if you really believe the virus is penetrating the mask and you’re breathing it in, how do you also believe your exhaled CO2 is getting ‘stuck?’ Viruses need a vector to spread; COVID-19’s vector is respiratory droplets; those droplets aren’t readily getting through a properly worn mask.

Actual results from a test

“I wore each mask for 5 minutes and checked my oxygen saturation (shown as the percentage below) along with my heart rate (HR, in beats per minute) using noninvasive pulse oximetry. Keep in mind, immediately prior to this, I had been wearing the surgical mask for five hours.

“Results:
• No mask: (oxygen level) 98%, HR (heart rate) 64;
• Surgical mask: 98%, HR 68;
• N95 mask: 99%, HR 69;
• N95 plus surgical mask (which is how most health care providers are wearing masks): 99%, HR 69.

Dr. Megan Hall, a pediatrician, conducted an experiment and posted the results on Facebook.

“There is no significant change in my oxygen saturation (or HR) in any scenario. Though may be inconvenient for some, you can still breathe.

“As a physician, I urge you and ask you to please wear a mask to protect yourself and those who cannot safely wear a mask.”

The Centers for Disease Control and Prevention (CDC) advises “cloth face coverings should not be worn by children under the age of 2 or anyone who has trouble breathing, is unconscious, incapacitated or otherwise unable to remove the mask without assistance.”

Those with underlying health issues that make it difficult for them to breathe are at the highest risk should they catch COVID-19. They are advised to stay home as much as possible, to maintain at least 6 feet of distance from others if they do go out in public and to avoid crowded places.

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