An exhaust manifold for an additive manufacturing system includes a manifold housing, at least one baffle movable relative to the manifold housing configured to modify an exhaust flow area defined in part by the at least one baffle, and an actuator operatively connected to the at least one baffle configured to move the at least one baffle. The manifold housing defines a housing channel. The at least one baffle can be one or more moveable baffles at least partially disposed within the housing channel and configured to move relative to the housing to modify a respective exhaust flow area of a respective baffle of the one or more moveable baffles. The actuator is operatively connected to each of the one or more movable baffles and configured to move the one or more movable baffles relative to the housing.