SAN ANTONIO Valve masks became popular toward the beginning of the COVID-19 pandemic response, but people are now being told not to use them. Wearing masks can be annoying, which is why people began turning to valve masks that have circular or square vents that allow for more comfortable breathing. Why experts say its false to say masks dont filter out coronavirus because odors can get inFrolichstein said he and his colleagues use normal N95 masks but never the ones with valves. So when people say valve masks offer two-way protection and are the best defense against COVID-19, that is false on our KSAT Trust Index. 6 charts explain COVID-19 surge in San AntonioCampbell said protecting the entire community to stop the spread of COVID-19 goes two ways, not one.