A filter cartridge has a filter medium that is formed in such a way that it surrounds a central through-passage, wherein the central through-passage has a first opening and ends at a cartridge base, and wherein the filter medium extends between the first opening and the cartridge base and thereby forms an elongated filter body, which may influence the average ascent speed of air and bring about an optimum filtration operation, wherein the filter medium is rectangular or square-shaped at one end of the filter cartridge and is rounded at the other end.