As more people appear to be wearing N95 face masks with higher expectations of warding off COVID-19 infections, a recent study indexed by the National Library of Medicine of the U.S. National Institutes of Health reveals some adverse effects about the N95 respirator mask. Importantly, disseminating information to the public about the risks as well as benefits of any medical intervention is necessary to enable people to make informed decisions before using the intervention.
The human body takes in substances from the environment, such as food, water, and air, to use in bodily functions, and the body expels substances back out into the environment as metabolic waste products following their use. The retention of waste products could be harmful to the body. This includes exhaled waste products of respiration—including carbon dioxide. Inhaling one’s own exhaled air creates a harmful buildup of carbon dioxide in the body, which is associated with symptoms of headache, dizziness, shortness of breath, and impaired cognitive function.
Of relevance, researchers reported that breathing with the N95 respirator mask causes excessive inhalation of carbon dioxide. Approximately seven times greater levels of carbon dioxide are inhaled compared to normal breathing! This occurs as air exhaled into the mask is prevented from mixing with surrounding fresh air: N95 respirator mask breathing leads to excessive carbon dioxide inhalation and reduced heat transfer in a human nasal cavity - PMC (nih.gov).
Another study found that accumulation of carbon dioxide from short-term use of face masks (15 minutes) did not exceed threshold limits set by the U.S. National Institute for Occupational Safety and Health (NIOSH). However, carbon dioxide levels exceeded long-term NIOSH limits of 5,000 ppm for eight hours: Carbon dioxide increases with face masks but remains below short-term NIOSH limits.
Due to limitations in the designs of both studies, the researchers recommended further investigations of effects from wearing face masks.
Hypothesis
Molecules of carbon dioxide are much smaller than virions, which are composed of lipids, proteins, and nucleic acids. If masks trap higher levels of carbon dioxide for inhalation, it seems likely that masks also trap larger virions shed through the breath. Additionally, it makes sense that if virions are prevented from passing into the mask from the outside air, virions exhaled into the mask must also be prevented from escaping out.
Could the inhalation of one’s own shed viruses trapped in a face mask contribute to the buildup of viral load, leading to an increased risk of viral infections? More studies are needed to investigate this hypothesis.
Dr. Ron Brown – Opinion Editorial