In a humid or poorly ventilated or labor-intensive work environment, using a mask with a breathing valve can help you feel more comfortable when exhaling. The working principle of the breathing valve is that the positive pressure of the exhaust gas during the exhalation blows off the valve sheet to quickly remove the exhaust gas from the body, reducing the stuffy feeling when using a mask, and the negative pressure when inhaling will automatically close the valve to avoid suction Pollutants entering the external environment.
