evidence: Contrary to viral claims, wearing surgical masks or cloth face coverings does not restrict the amount of oxygen a person breathes in, nor does it cause a dangerous buildup of carbon dioxide, according to a study published Friday in the journal Annals of the American Thoracic Society. [...] Some residents argued against the order, suggesting that wearing masks could lead people to inhale too much carbon dioxide. At least one other resident said without evidence that masks were "literally killing people." [...] Campos and colleagues tested the effects of wearing a typical surgical mask on the body's ability to take in oxygen and exhale carbon dioxide.