In a viral video on Facebook, Jeff Neff, a candidate for the Pennsylvania State Senate, measured the oxygen levels behind various masks and concluded that “No matter what you choose: head socks, stylish neoprene mask, mask cheap, N-95, best available: none of them allow you to breathe the required oxygen level. “
In the video, Neff used an MSA ALTAIR 5X multigas detector, a device produced by MSA Safety Inc., to measure the oxygen levels behind different types of masks while wearing them. A typical atmospheric oxygen concentration level is approximately 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 below that level. However, MSA Safety says Neff misused the ALTAIR 5X and that the readings it 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 within a face covering,” reported Samantha D’Uva, MSA representative Verification of shipping facts. D’Uva clearly stated that “although the ALTAIR 5X detects 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 set the ALTAIR 5X in oxygen alarm. The same would happen if you just exhaled on the sample line. Due to the response and recovery time of the oxygen sensor, combined with the small space inside the mask, the readings would not have time to restart before the next exhalation, resulting in a continuous alarm. “
If an adequate measurement of oxygen had been taken, you would find what virtually every expert has claimed since rumors like this began: face masks do not obstruct the flow of oxygen or cause dangerous levels of carbon dioxide inhalation. When asked if the masks pose a risk to users, Dr. Thomas Bice, an assistant professor of medicine specializing in prolonged mechanical ventilation and lung disease at the University of North Carolina Chapel Hill School of Medicine, replied: ” Will they catch my eye? Roll? “
“The size of an oxygen molecule is so small that there is no way that a mask can restrict the movement of oxygen through the mask,” Bice said. Verification of shipping facts. “There may be a slight increase in carbon dioxide levels inside the mask relative to the outside, but that would be so small that it would not cause any problems.”
Bice noted that the ALTAIR 5X breathes directly, so its measurements are affected by the increased carbon dioxide content of the exhaled air. In particular, the oxygen value drops and then remains constant in each of Neff’s mask experiments. “Now, if I really had difficulty breathing and getting enough oxygen, that value would go down, it would continue to go down,” Bice said. “I think the fact that it stays constant … shows that despite repeated inhalation and exhalation there is no use of oxygen within that mask.”
The purpose of any type of mask, from the N95 to the somewhat less effective cloth masks that are widely used, is to prevent droplets from passing through the mask. “The drops that we are concerned with are the size of, say, 5 to 10 microns, or micrometers … one millionth of a meter, very small,” Bice said. “Oxygen and carbon dioxide are measured in size in the range of picometers … a million of them would fit within a micrometer. So oxygen and carbon dioxide are much smaller than the drops we are concerned with keeping out. “
If one wanted to accurately measure whether someone with a mask was obtaining safe levels of oxygen, according to Bice, the best tool to use would be a pulse oximeter, which detects hemoglobin that has bound to oxygen in the blood. This would provide a more useful metric than just measuring oxygen levels behind a mask, Bice said, because “it’s not just a matter of what’s in front of your mouth, it’s a matter of whether your lungs can oxygenate the body.” And the good news is that your lungs can do a phenomenal job and use significantly less oxygen than even 19 percent and still maintain oxygen saturation. Even if 19 percent was what was right in front [Neff’s] mouth while wearing the mask for 10 minutes, there is no reason to think that your body would not receive enough oxygen. “
The MSA ALTAIR 5X multigas detector was incorrectly used in the viral video and was unable to produce an accurate reading of oxygen levels under those circumstances. However, more accurate research has shown that wearing a mask does not pose a threat to your oxygen levels and is an important tool in preventing the spread of the coronavirus.
