So this is specifically about masks with valves, which are different from cloth masks. These masks typically have a mechanism which opens when the wearer exhales, which defeats the purpose of you or I wearing masks. The goal is to contain droplets which could infect other people, so if there's a valve that opens every time you exhale, it's not going to do anything. These sorts of masks are specifically designed as protective to the wearer with no concern for what the wearer might be putting back into the environment.