A filter system for ambient air to remove airborne particulates in air that is to be used for engine operation. A filter media that is pervious to air and impervious to the particulates may be coupled to a filtered air chamber, which in turn may supply filtered air to the engine's air intake system. In various embodiments, the engine's air intake may be used utilized to draw air through the filter media into the filtered air chamber. An pressurized gas pulsing system may be used to periodically urge reverse airflow through the bag walls to maintain the permeability of the walls to the clean air.