An air intake system for directing intake air to an internal combustion engine of a machine is disclosed. The air intake system may comprise an air compressor configured to increase a pressure of the intake air, and a membrane unit downstream of the air compressor and having a membrane with selectivity for siloxanes. The membrane may have a first side and a second side, and the first side may be exposed to a higher pressure than the second side when the air compressor is operating. The membrane may be configured to separate the intake air into a permeate that traverses the membrane from the first side to the second side, and a retenate that remains on the first side. The permeate may have a higher siloxane content than the retenate. The retenate may be directed to the internal combustion engine for combustion.