Are the average carbon dioxide levels inhaled by people wearing N95 masks higher than OSHA's work shift limit for carbon dioxide?
N95 masks are commonly worn in medical facilities, and OSHA requires employers to conduct a medical evaluation of each employee who wears them because they "may place a burden on an employee's health." Without any health warnings, CNN is now instructing the general public to wear N95 masks to protect against the Omicron variant. A study published in 2013 by the Annals of Occupational Hygiene found that the CO2 levels in the breathing zones of 30 different models of N95 masks ranged from 1.3% to 3.5%. This is 2.6 to 7.0 times OSHA's 0.5% work shift limit for CO2. It is also 13 to 35 times the 0.1% classroom limit for CO2 in many countries and about 30 to 80 times the 0.04% level of CO2 in fresh air. Studies published in scientific journals have found that N95 masks and the levels of CO2 in them cause headaches, "large and statistically significant reductions" in complex decision-making ability, cardio-pulmonary stress, and possible fatal cardiac events among people with heart disease.