... concluded that there was ample evidence for adverse effects of wearing such masks. 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.
JAMA Pediatrics. Published online June 30, 2021
Experimental Assessment of Carbon Dioxide Content in Inhaled Air With or Without Face Masks in Healthy Children. A Randomized Clinical Trial
Many governments have made nose and mouth covering or face masks compulsory for schoolchildren. The evidence base for this is weak.1,2 The question whether nose and mouth covering increases carbon dioxide in inhaled air is crucial. A large-scale survey3 in Germany of adverse effects in parents and children using data of 25 930 children has shown that 68% of the participating children had problems when wearing nose and mouth coverings.
The normal content of carbon dioxide in the open is about 0.04% by volume (ie, 400 ppm). A level of 0.2% by volume or 2000 ppm is the limit for closed rooms according to the German Federal Environmental Office, and everything beyond this level is unacceptable.4