Bay Area says masks with valves are not acceptable face protection amid the coronavirus pandemic because they allow your breath to escape and endanger those around you
- Six counties in the San Francisco Bay Area have required residents to wear face coverings in public during the coronavirus pandemic
- Officials say N-95 respirators with one-way valves that allow exhalation to escape don’t provide adequate protection
- If an infected person wearing the mask coughs or sneezes, droplets can travel through the air and infect others
- In the US, there are more than 1.01 million confirmed cases of the virus and more than 56,000 deaths
- Here’s how to help people impacted by Covid-19
The San Francisco Bay Area has become the first region in the US to say that masks with valves are not acceptable face protection amid the coronavirus pandemic.
Last week, six counties in the region – home to more than five million Americans – mandated that residents cover their faces in public.
The pieces, made of plastic and rubber, make breathing easier because they allow exhaled carbon dioxide to escape.
But officials say the masks do not provide adequate protection because, although they prevent some pathogens from getting in, they allow your droplets to get out, which could potentially infect others.
The San Francisco Bay Area has become the first in the US to say N-95 respirators with one-way valve that allow exhalation to escape (pictured) are not adequate face protection
If an infected person wearing the mask coughs or sneezes, droplets can travel through the air and infect others. Pictured: Boston EMS medics work to resuscitate a patient on the way to the ambulance amid the coronavirus disease (COVID-19) outbreak in Boston, Massachusett
Some masks and respirators come with valves, which are made of a plastic base, a rubber middle and a plastic cover.
When you breathe in, the plastic cover closes so any pathogens in the air can’t get in. However, when you exhale, the cover opens so carbon dioxide can escape.
The valve feature is also meant to reduce humidity and moisture than can build up inside a mask.
If an uninfected person wears an N-95 respirator, or another mask, and an infected person doesn’t, the risk of transmission is reduced by 30 percent.
If the infected person wears a mask and an uninfected person doesn’t, the risk decreases by 95 percent. If both wear masks, risk of transmission could fall as low as 1.5 percent.
However, N-95 respirators with one-way exhalation valves present a serious public health hazard.
The virus is most commonly spread via respiratory droplets, which can linger in the air for up to three hours, according to the National Institutes of Health.
This means if an infected person wars the masks coughs or sneezes, the valve can allow droplets to escape and potentially infect others.
‘Given that most of the value of these masks is not to protect the wearer but to protect others from a potentially contagious asymptomatic wearer, those one-way valves make the masks practically useless for protecting others,’ Dr Matthew Springer, a cardiologist at UCSF told the San Francisco Chronicle.
‘So all those potentially contagious people are spewing unfettered large respiratory droplets, probably even in a concentrated stream going through the valves.’
Even the Centers for Disease Control and Prevention recommend that hospitals not use N-95 masks with valves.
‘Respirators with exhalation valves should not be used in situations where a sterile field must be maintained (e.g., during an invasive procedure in an operating or procedure room) because the exhalation valve allows unfiltered exhaled air to escape into the sterile field,’ a statement on its website reads.
In the US, there are currently more than 1.01 million confirmed cases of the virus and more than 56,000 deaths.