Abstract: A lightweight cigarette filter including a filter element containing filter material having a total Denier of less than 35,000 or a bulk density of less than 0.12 gcm.sup.-3 in which part of the volume of the filter is occupied by a space filler impervious to smoke flow therethrough and the bulk density of which is less than the bulk density of the equivalent amount of filter material which it replaces.

Abstract: A method of making a ventilated cigarette filter plug in which a bore is thermally formed, by a laser beam for example, in a rod comprising a duct extending coaxially of the rod and matrix material surrounding the duct. The thermally formed bore extends through the matrix material to provide air-flow communication between the periphery of the rod and the interior of the duct.

Abstract: A smoking article mouthpiece element comprises a first portion within which a smoke-passage and a ventilation-duct extends from end-to-end of the portion, a downstream end of the duct being spaced from the periphery of the first portion and the wall and the walls of the duct being gas impervious and a second portion disposed at the end of the first portion being in smoke-flow communication with the smoke passage of the first portion, and gas-impervious wall at the end of said second portion closer to the first portion extending inwardly from a first location at the periphery of the element to a second location at the side of the upstream end of the duct further from the first location, the wall bounding a cavity in communication with the duct and segregated from the interior of the second portion. The first and second portions may form respective parts of an integral unit or may be discrete components disposed in end-to-end abutment. The aforesaid wall is suitably part of the second portion.

Abstract: A mouthpiece element for a cigarette comprises a duct which extends from the periphery of the element at a first location, spaced from the mouth end of the element, to the mouth end of the element at a second location, spaced from the periphery of the element. The element is attached to a cigarette rod by tipping which permits the ingress of air to the duct at the first location. Preferably, during smoking the ratio of the velocity of air issuing from the duct at the second location to the velocity of smoke issuing from the mouth end of the element is in excess of at least ten.

Abstract: Cigarette filters comprises a filter element, open for smoke flow at the mouth end, and smoke passage of flow impedance less than that of the filter element. The passage is closed at the downstream end so that smoke is constrained to pass into the element at the downstream end of the passage. The passage may be an annular cross-section duct or grooves at the periphery of the element or may be a bore within the element. The filters provide an increasing degree of filtration as smoking proceeds.

Abstract: A smoking article mouthpiece comprises a smoke passage and a ventilation air duct, both of which extend from end-to-end of the mouthpiece. The duct is of a depth of 25% or more of the diameter of the mouthpiece. When the mouthpiece is incorporated in a smoking article such that air may enter the duct, the ratio of the velocities of air and smoke is in excess of ten. The mouthpiece may also comprise a ventilation-air collection groove which extends about the element and opens into the ventilation air duct.

Abstract: A smoking article mouthpiece comprises a smoke passage extending from end-to-end of the element and first and second ventilation ducts. The first ventilation ducts extend from the periphery of the element to the downstream end of the element at locations spaced inwardly from the periphery. The second ventilation ducts extend from the periphery to the upstream end of the element.