Valve masks are commonly used in construction and other work, they are not suitable for coronavirus
Valve masks do not prevent the transmission of the coronavirus from those who wear it to other people. People should wear masks to ‘break’ the spread of Covid-19 disease caused by SARS-CoV-2 coronavirus, but face masks should not have a valve, stresses the US Centers for Disease Control and Prevention with its new announcement.
Valve masks are commonly used in construction and other work, allowing users to inhale filtered air and exhale hot liquid air through the valve, which reduces heat and humidity inside the mask. Thus, the mask becomes more comfortable and can be worn for a long time, without causing discomfort.
But the mask with a valve is not suitable in an epidemic, because it does not help prevent the transmission of a virus. In the times of Covid-19 the use of a mask is necessary to prevent droplets from being ejected by a carrier of the virus, either symptomatic or asymptomatic and not to travel in the air, so it can infect other people. The droplets are ejected not only by coughing or sneezing, but also simply by speech.
But when the mask has a valve, it does not prevent the droplets from diffusing into the air and then being inhaled by unsuspecting people, especially those who move without a mask. That’s why, after all, medical masks do not have a valve.
Many airlines have already banned their passengers from wearing a valve mask, most recently American Airlines, which has announced it will do so from August 19.