Respiratory valve masks are not able to prevent coronavirus. Whether a mask can prevent coronavirus mainly depends on the material and the standard used. Currently, only disposable medical masks, surgical masks, N95 or KN95 masks are used to block the droplet transmission route of coronavirus under the new coronavirus epidemic. However, masks with breathing valves are precisely not recommended for use and are not conducive to epidemic prevention and control. Masks with breathing valves are one-way protection, which means that they only protect the patient wearing them, but not the people around them. It means that the valve is closed when inhaling to protect from outside bacteria and viruses, but when exhaling the valve is open, if the patient is infected by the new coronavirus, the virus droplets will go into the air without reservation to make the surrounding people have the risk of infection.