Fresh/Recirculated Air Control Lever
WARNING: This page is about a different car, the 2001 Subaru Impreza and 2000 Subaru Impreza. However, it is still accessible from the selected car via links, so may be relevant.
When lever is placed in recirculated air position, it allows recirculated interior air to flow through instrument panel outlets. When lever is placed in fresh air position, it allows outside air to flow through instrument panel outlets.