as shown in fig1 and 2 , a smoking article 10 is comprised of a tobacco section 12 , a heated catalysis section 14 , a cooling section 16 , and a filter section 18 . a cigarette wrapper 22 encases tobacco 32 and extends towards the mouth end of the cigarette . cigarette wrapper 22 also encases a cooling chamber 36 adjacent to the filter section 18 . an external heat source , such as a heating pad 22 , circumscribes the catalyst bed 34 . the portable heating pad 24 generally includes a self - sustaining solid - solid or solid - liquid exothermic reactor packed in a disposable wrapper . the catalyst bed 34 is generally in the form of meshes , honeycombed structures , granules , and the like . the particular catalyst for making up the meshes or honeycombed structures is determined by the specific smoke components which are to be reformed . the ability to alter specific smoke components depends on the nature of the catalyst , the effective surface area of the catalyst , and its surface temperature . for example , oxidation / reduction catalyst reduce nox and oxide co . low temperature co oxidation catalyst include base and noble metal oxides . platinum and / or palladium metals and metal alloys coated on metal substrates are usable for oxidation - reduction catalyst . the degree of conversion of the smoke components depends on the specific type catalyst and reaction temperature employed . depending upon the desired extent of smoke chemistry modification , the catalyst bed may include a plurality of different types of catalysts . in the smoking of a smoking article , as set forth in fig1 and 2 , the lighting end or tobacco end of the smoking article 10 is lit and the smoke passes from the tobacco section 12 into the catalyst section 14 which is heated by a heating pad 24 to at least 100 ° c . and controlled in a desired temperature range wherein selected smoke components reform as they pass through the catalyst bed 34 . the mainstream smoke , including the reformed smoke components , is then cooled in the cooling section 16 prior to entering the filter section 18 . in the filter section 18 , the particulates and condensible materials are removed from the smoke stream prior to entering the mouth of the smoker . in fig3 is shown a second embodiment of the present invention wherein a smoking article 110 differs from the smoking article 10 in that a flavor section 116 is disposed between the heated catalyst section 14 and the filter section 18 . the flavor section 116 includes a flavor source 136 which may be tobacco or any other flavor source which will be vaporized upon contact with the mainstream smoke which is the by - product of combustion of the tobacco 32 in the tobacco section 12 . in fig4 is shown a smoking article 210 which differs from the smoking article 10 and 110 of fig2 and 3 , respectively , in that the tobacco section 212 is provided with tobacco 232 and a central hollow section 242 which extends from the terminating or lighting end of tobacco section 212 to the catalyst bed 234 . the mainstream smoke from the tobacco section 212 flows through the channel 242 and upon contacting the catalyst bed 234 , catalytic after - burning takes place resulting in the oxidation of co and reduction of nox . the quality of the reform smoke depends , however , on the specific catalyst and its temperature . in fig5 is another embodiment of the present invention . the smoking article 310 is a modification of the smoking article 210 of fig4 wherein a flavor section 116 , including a flavor source , such as tobacco 136 , is disposed between the catalyst 234 and the filter section 18 . the foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention and scope of the appended claims .
a smoking article includes a tobacco rod in axial alignment with a filter section with a catalyst bed disposed between the tobacco rod and the filter section . the catalyst bed may be heated from an external portable heating source or may be heated by the internal evolving gases of combustion of the tobacco .