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Killer COVID-19 Masks? The Truth About Trapped Carbon Dioxide

June 22, 2020

COVID-19 can kill. Now, according to a misguided Internet-fueled theory, masks can kill, too.

All it takes is a mask-wearer who inhales freshly exhaled carbon dioxide repeatedly until dizzy, unconscious or dead. That, no doubt, would be a shocking development. In the real world, the average mask user without preexisting respiratory illness has nothing to worry about — except COVID-19.

Only an airtight mask could possibly cause any breathing difficulty. That eliminates cloth masks, the preferred personal protective equipment in public. It actually eliminates N95 respirators, too, usually reserved for healthcare 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.

But who wouldn’t want a more comfortable N95? John Xu, a research scientist at Stanford University, is developing a modified N95 mask with his colleagues that includes a small box worn at the waist with a tube extending to the mask. The box, through an electrochemical process, produces pure oxygen to compensate for the loss of oxygen caused by the mask. The researchers started their project with the assumption that an N95 mask reduces oxygen intake by anywhere from 5 percent to 20 percent.

An N95 mask could possibly cause:

Hypoxia: When body tissue does not get enough oxygen.

Hypercapnia: Elevated levels of carbon dioxide in the blood that can cause dizziness, shortness of breath, headache and, in extreme cases, hyperventilation, seizures and possible death.

But even an N95 mask is unlikely to produce such extreme reactions. A respiratory illness such as chronic obstructive pulmonary disease, or COPD, can cause both hypoxia and hypercapnia. Those with a preexisting condition who experience breathing difficulties, of course, would almost certainly remove the mask.

A Centers for Disease Control and Prevention representative told Reuters that carbon dioxide, indeed, will collect between the mask and face but not in dangerous amounts and certainly not enough to cause hypercapnia. A mask is designed to trap viral droplets, much larger than tiny carbon dioxide particles. A mask, either N95 or cloth, cannot trap all carbon dioxide particles — they either go through the mask or escape along the mask’s perimeter.

The CDC still recommends cloth masks in public, with these exceptions:

  • Children under age 2.
  • Anyone exhibiting breathing difficulties or otherwise incapacitated.

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