A passive fuel additives dosing system includes a membrane-based contactor within a cartridge, an additive within the membrane-based contactor, a fuel inlet to the cartridge and a fuel outlet from the cartridge. The membrane-based contactor is arranged within the cartridge such that, with fuel in the cartridge, a fuel contact area with the membrane-based contactor is dependent on a fuel flow rate to passively dispense a proportional amount of the additive into the fuel.