Is there a risk to the breathing valve on the mask?

Q: Will the breathing valve on the mask worn pose a risk to the surrounding population?    

A: The exhalation valve of the breathing valve type mask is a one-way valve. When exhaling, the positive pressure of the expired gas blows the valve piece open and rapidly expels the exhaled gas. The exhalation process may expel the virus if the patient wears this mask because there is no filtering layer. This type of mask should not be worn by confirmed and suspected patients.