Does your face mask have vents or valves?
The Centers for Disease Control and Prevention (CDC) recently updated its guidelines advising Americans to avoid such face masks, as they aren’t as effective in preventing the spread of COVID-19.
“The purpose of masks is to keep respiratory droplets from reaching others to aid with source control. Masks with one-way valves or vents allow exhaled air to be expelled out through holes in the material. This can allow exhaled respiratory droplets to reach others and potentially spread the COVID-19 virus,” the federal agency states in its guidance.
“Therefore, CDC does not recommend using masks if they have an exhalation valve or vent.”
The CDC’s guidance comes after N95 respirators with small valves on the front became the target of a similar warning from a local health department in May.
Though valves make masks a bit more breathable, “they don’t do anything in terms of filtering out anything the wearer is exhaling,” Dr. Ali Raj, executive vice chairman of the department of medicine at Mass. General Hospital, told the Boston Globe in May.
“When you’ve got people coming out and businesses opening back up, you might as well have people not wearing masks at all if they’ve got a one-way valve because they’re just breathing everything right out into the air without any filtration,” he added.
At the time, the San Francisco Department of Public Health took to Twitter to remind residents that if they are choosing to wear an N95 (which should ideally be reserved for medical workers on the frontline, officials have stressed), they should ensure it doesn’t have the front valve.
Valved N95 masks are not typically used in a medical setting, though they are said to make breathing easier, according to a 2008 study on the masks. In general, N95s help to “reduce the wearer’s exposure to airborne particles, from small particle aerosols to large droplets,” according to the CDC.