Air filtration devices and systems are provided to filter conditioned air after air exits an air conditioner module located on a ground support equipment unit but prior to entering a grounded aircraft. Disclosed embodiments include a system with the air filtration unit located along a hose originating from an aircraft ground support unit and a system with the air filtration unit located along a hose originating from an aircraft. Certain embodiments of the air filtration unit include a diffuser, which is configured to couple to a filter and direct air through the filter during operation.