Mandating children to wear facemasks for long periods of time while at school and participating in other activities is an unprecedented move, one that was put into place despite no research showing the practice is safe. It’s not simply a case of “something is better than nothing,” because the act of mask wearing comes with a risk of adverse effects.

Now that the pandemic is more than a year behind us, evidence is starting to accumulate showing that the use of face masks in children may cause more harm than good. One of the latest studies noted that the evidence base for making face masks compulsory in schoolchildren is “weak,” and looked into their effects on carbon dioxide in inhaled air.¹

Masks Increase Carbon Dioxide Inhalation

Your body produces carbon dioxide (CO2) as a byproduct of cellular function.² This odorless, colorless gas is then transported via your blood to your lungs, where it is exhaled from your body. Normally, the CO2 then dissipates into the air around you before you take another breath. In the open air, carbon dioxide typically exists at about 400 parts per million (ppm), or 0.04% by volume.

The German Federal Environmental Office set a limit of CO2 for closed rooms of 2,000 ppm, or 0.2% by volume. If you’re wearing a facemask, the CO2 cannot escape as it usually does and instead becomes trapped in the mask. In a study published in JAMA Pediatrics, researchers analyzed the CO2 content of inhaled air among children wearing two types of masks, as well as wearing no mask.³

Children in the study ranged in age from 6 to 17 years, with a mean age of 10.7. While no significant difference in CO2 was found between the two types of masks, there was a significant elevation when wearing masks compared to not wearing them.

CO2 in inhaled air under surgical and filtering facepiece masks came in between 13,120 ppm and 13,910 ppm, “which is higher than what is already deemed unacceptable by the German Federal Environmental Office by a factor of 6,” the researchers noted.⁴ Also important, this level was reached after only three minutes, while children wear masks at school for a mean of 270 minutes at a time.

Even the child who had the lowest measured CO2 level had a measurement threefold greater than the closed room CO2 limit of 0.2%. However, younger children appeared to have the highest CO2 values; a level of 25,000 ppm was measured from a 7-year-old wearing a facemask.⁵

The study attracted criticism and calls for retraction by those questioning mask risks to children, but in a thoughtful synopsis by Dr. Vinay Prasad, a hematologist-oncologist and associate professor of medicine at the University of California San Francisco, it’s noted that there are both benefits and risks to forcing children to wear masks.⁶

While large, empirical studies could answer the question of whether masks help or harm children, “we did literally zero of them,” Prasad said, and the CO2 study is attempting to add some clarity. He added:⁷

“Here is the real answer to the question of whether it’s worth it to mask kids: No one has any clue. During the last year and half, the scientific community has failed to answer these questions. Failed entirely.

We have no idea if masks work for 2-year-olds and above, 5 and above, 12 and above. No idea if they only work for some period of time. No idea if this is linked to community rates. No idea if the concerns over language loss offset the gains in reduced viral transmission, and if so, for what ages.”

Children’s Mask Complaints Could Be Caused by Elevated CO2

A German study using data from 25,930 children showed that 68% reported adverse effects from wearing facemasks.⁸ Among them, 29.7% reported feeling short of breath, 26.4% being dizzy and 17.9% were unwilling to move or play.⁹

Hundreds more experienced “accelerated respiration, tightness in chest, weakness and short-term impairment of consciousness.” Additional symptoms were also reported among the children, who wore facemasks for an average of 270 minutes a day:¹⁰

Irritability (60%)	Headaches (53%)
Difficulty concentrating (50%)	Less happiness (49%)
Reluctance to go to school/kindergarten (44%)	Malaise (42%)
Impaired learning (38%)	Drowsiness or fatigue (37%)

Signs of mild to moderate hypercapnia, which is a buildup of CO2 in your bloodstream, include shortness of breath, daytime sluggishness, headache, daytime sleepiness and anxiety.¹¹

Hypercapnia is often associated with chronic obstructive pulmonary disease (COPD), which makes it harder for you to breathe, but it can also be caused by activities that limit you from breathing fresh air, such as scuba diving or being on a ventilator.^12,13 The researchers of the featured study believe, however, that the use of facemasks could lead to “impairments attributable to hypercapnia,” adding:¹⁴

“Most of the complaints reported by children can be understood as consequences of elevated carbon dioxide levels in inhaled air. This is because of the dead-space volume of the masks, which collects exhaled carbon dioxide quickly after a short time.

This carbon dioxide mixes with fresh air and elevates the carbon dioxide content of inhaled air under the mask, and this was more pronounced in this study for younger children … We suggest that decision-makers weigh the hard evidence produced by these experimental measurements accordingly, which suggest that children should not be forced to wear face masks.”