A system for a vehicle, having a fuel cell system and a compressed air system for supplying compressed air to a pneumatic device, said fuel cell system comprising: at least one fuel cell having an anode side and a cathode side, an air inlet conduit connected to an inlet end of the cathode side for supplying air to the cathode side of the at least one fuel cell, an air compressor disposed in the air inlet conduit, an air filter arranged to receive air from an ambient environment, said air filter being arranged at an inlet of the air inlet conduit and upstream said air compressor, a fluid outlet conduit connected between an outlet end of the cathode side and an inlet side of an expander for supply of an exhaust flow from the cathode side to the expander, and an exhaust conduit connected to an exhaust side of the expander; said compressed air system comprising: an electrically operable air compressor connectable to the pneumatic device; wherein the system further comprises a controllable valve assembly for fluidly connecting an air inlet of the electrically operable air compressor to multiple fluid supply positions, said multiple fluid supply fluid positions comprising at least two positions selected from an outlet conduit position upstream the inlet side of the expander, an air inlet conduit position upstream the air compressor, an air inlet conduit position downstream the air compressor and a position in fluid communication with an independent air filter in fluid communication with the ambient environment, and wherein the controllable valve assembly is configured to selectively direct air from the multiple fluid supply positions (180, 184, 186, 188) to the compressed air system in response to an operating condition of the vehicle. said fuel cell system comprising: at least one fuel cell having an anode side and a cathode side, an air inlet conduit connected to an inlet end of the cathode side for supplying air to the cathode side of the at least one fuel cell, an air compressor disposed in the air inlet conduit, an air filter arranged to receive air from an ambient environment, said air filter being arranged at an inlet of the air inlet conduit and upstream said air compressor, a fluid outlet conduit connected between an outlet end of the cathode side and an inlet side of an expander for supply of an exhaust flow from the cathode side to the expander, and an exhaust conduit connected to an exhaust side of the expander; at least one fuel cell having an anode side and a cathode side, an air inlet conduit connected to an inlet end of the cathode side for supplying air to the cathode side of the at least one fuel cell, an air compressor disposed in the air inlet conduit, an air filter arranged to receive air from an ambient environment, said air filter being arranged at an inlet of the air inlet conduit and upstream said air compressor, a fluid outlet conduit connected between an outlet end of the cathode side and an inlet side of an expander for supply of an exhaust flow from the cathode side to the expander, and an exhaust conduit connected to an exhaust side of the expander; said compressed air system comprising: an electrically operable air compressor connectable to the pneumatic device; wherein the system further comprises a controllable valve assembly for fluidly connecting an air inlet of the electrically operable air compressor to multiple fluid supply positions, said multiple fluid supply fluid positions comprising at least two positions selected from an outlet conduit position upstream the inlet side of the expander, an air inlet conduit position upstream the air compressor, an air inlet conduit position downstream the air compressor and a position in fluid communication with an independent air filter in fluid communication with the ambient environment, and wherein the controllable valve assembly is configured to selectively direct air from the multiple fluid supply positions (180, 184, 186, 188) to the compressed air system in response to an operating condition of the vehicle. an electrically operable air compressor connectable to the pneumatic device; wherein the system further comprises a controllable valve assembly for fluidly connecting an air inlet of the electrically operable air compressor to multiple fluid supply positions, said multiple fluid supply fluid positions comprising at least two positions selected from an outlet conduit position upstream the inlet side of the expander, an air inlet conduit position upstream the air compressor, an air inlet conduit position downstream the air compressor and a position in fluid communication with an independent air filter in fluid communication with the ambient environment, and wherein the controllable valve assembly is configured to selectively direct air from the multiple fluid supply positions (180, 184, 186, 188) to the compressed air system in response to an operating condition of the vehicle.