Filtering face mask that has a new exhalation valve

Filtering face mask has a mask body and an exhalation valve The mask body is adapted to fit over the nose and mouth of a person, and the exhalation valve is attached to the mask body The exhalation valve has a valve seat and a single flexible flap The valve seat includes a seal surface and an orifice The orifice is circumscribed by the seal surface The single flexible flap has a fixed portion and one free portion The one free portion has a free end, and the fixed portion is located off-center of the flexible flap away from the free end and is secured to the valve seat outside the orifice The one free portion is pressed toward the seal surface when the wearer is neither inhaling or exhaling. The free portion can be lifted from the seal surface during an exhalation. Because the flexible flap is mounted to the valve seat off-center and outside the orifice and yet is pressed towards the valve seat when the wearer is not inhaling or exhaling, the face mask can demonstrate a lower air flow resistance force during an exhalation which enables the exhalation valve to open easier, and it can remain closed under any static orientation of the valve to prevent contaminants from entering the mask interior.