Are the average carbon dioxide concentrations in the N95 masks commonly worn by healthcare workers high enough to impair their ability to make complex decisions?
A study published in 2013 by the Annals of Occupational Hygiene measured CO2 levels in the breathing zones of 30 different models of N95 masks. Buried 10 pages deep into their paper, the authors revealed that the average CO2 concentrations in these masks ranged from 1.3% to 3.5%. This is 5 to 14 times higher than the 0.25% CO2 level found to cause "large and statistically significant reductions" in complex decision-making ability by a 2012 study in the journal Environmental Health Perspectives. Likewise, a study published by the journal Nature in 2018 found that the same CO2 level (0.25%) caused a marked decline in the ability of commercial aircraft pilots to perform complex flight maneuvers. Based on a systematic literature review published by the Journal of Patient Safety in 2013, "there are at least 210,000 lethal" errors in U.S. hospitals each year, and "the true number" is "estimated at more than 400,000 per year."