Do Masks Make It Impossible to Breathe in Enough Oxygen?

In a viral video on Facebook, Jeff Neff, a candidate for Pennsylvania State Senate, measured the oxygen levels behind various masks and concluded that “No matter what you choose—head sock, neoprene-type fancy mask, cheap mask, N-95, the best available—none of them allow you to breathe in the required oxygen level.”

In the video, Neff used an MSA ALTAIR 5X Multigas Detector, a device produced by MSA Safety Inc., to measure oxygen levels behind different types of masks as he wears them. A typical atmospheric oxygen concentration level is about 21 percent, while the Occupational Safety and Health Administration defines an oxygen deficient environment as one in which that level is below 19.5 percent. Neff measured the oxygen concentration behind each mask as being below that level. However, MSA Safety says Neff misused the ALTAIR 5X and that the readings he produced are inaccurate. The product is intended to “detect potentially hazardous or combustible atmospheres in factories, rooms, work areas, and confined spaces much larger than the area inside a face covering,” Samantha D’Uva, a representative for MSA informed The Dispatch Fact Check. D’Uva said, quite plainly, that “Although the ALTAIR 5X detects the ambient levels of oxygen, carbon monoxide and other gases, it is not designed for the use shown [in the video].” She explained:

“When used to sample the air behind a face mask, the wearer’s exhaled breath would displace oxygen and subsequently put the ALTAIR 5X into oxygen alarm. The same thing would happen if you simply exhaled into the sample line. Due to the response and recovery time of the oxygen sensor, combined with the small space inside of the mask, the readings would not have time to reset before the next exhalation, resulting in a continuous alarm.”

If a proper measurement of oxygen had been taken, it would find what virtually every expert has affirmed since rumors like this began: Face masks do not obstruct oxygen flow or cause dangerous levels of carbon dioxide inhalation. When asked if masks pose a risk to wearers, Dr. Thomas Bice, an assistant professor of medicine specializing in prolonged mechanical ventilation and pulmonary diseases at the University of North Carolina Chapel Hill’s medical school, responded: “Will you be able to capture my eye roll?”