The Airinum Urban Air Mask has 2 exhalation valves which act as ventilation systems for the mask - removing moisture, heat and carbon dioxide to make the mask easier to breathe through. 

When you breathe, the valves are transporting out the exhaled air to prevent the mask from becoming warm and moisty. The valves are engineered to only transport out the exhaled air, and not let any unfiltered air to sneak in.