The tester uses an Ibrid air quality monitor approved by OSHA. The US Occupational Safety and Health Administration (OSHA) creates air monitoring requirements to protect workers in the US from health and safety risks due to air pollution at the workplace. According to the tester, OSHA requires a minimum 19.5 reading for oxygen in order for workers to be allowed to work in a space. He tests the oxygen available while wearing the mask and obtains a reading of 17.4, which, he says, would explain people complaining of headaches while wearing the masks.
“The widespread use of cloth masks by healthcare workers may actually put them at increased risk of respiratory illness and viral infections and their global use should be discouraged, according to a UNSW study.”