An exhalation valve assembly (800) that controls the pressure of exhaled gas in a ventilation system is described. The exhalation valve assembly includes an actuator module (802) that may be fixed to the ventilation system and a valve module (804), removable for cleaning or disposal, through which the exhaled gas flows and that controls the pressure and release of the exhaled gas to the environment. Other components may also be incorporated into the assembly including a filter module (874), a flow meter and a condensate trap (864).
