evidence: Does Wearing a Face Mask Limit Your Oxygen Intake? [...] The risk to the general adult population of having significantly abnormal levels of oxygen or carbon dioxide when wearing a cloth or surgical mask is near zero, says Steven L. Shein, MD, Division Chief of Pediatric Critical Care Medicine at UH Rainbow Babies & Children's Hospital. [...] The study,The Effects of Wearing Facemasks on Oxygenation and Ventilation at Rest and During Physical Activity, was published in the journal PLOS ONE. The study was supported financially by UH Rainbow Department of Pediatrics.