http://patft.uspto.gov/netahtml/PTO/srchnum.htm
US 6,789,548 Sept 14 2004 Method of making a smoking composition " The present invention relates to smoking articles such as cigarettes, and in particular to catalytic systems containing metallic or carbonaceous particles that reduce the content of certain harmful or carcinogenic substances, including polyaromatic hydrocarbons, tobacco-specific nitrosamines, carbazole, phenol, and catechol, in both mainstream cigarette smoke and side stream cigarette smoke." "In preferred embodiments, the nitrate or nitrite source includes a nitrate of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, yttrium, lanthanum, cerium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, erbium, scandium, manganese, iron, rhodium, palladium, copper, zinc, aluminum, gallium, tin, bismuth, hydrates thereof and mixtures thereof. Preferably, the nitrate salt may be an alkali or alkaline earth metal nitrate." "One approach to removing undesired components from tobacco smoke is the use of catalysts. Palladium catalyst systems have been proposed for cigarettes. The following patents describe such systems: U.S. Pat. No. 4,257,430 to Collins et al.; U.S. Pat. No. 4,248,251 to Bryant et al.; U.S. Pat. No. 4,235,251 to Bryant et al.; U.S. Pat. No. 4,216,784 to Norman et al.; U.S. Pat. No. 4,177,822 to Bryant et al.; and U.S. Pat. No. 4,055,191 to Norman et al., each of which is incorporated by reference in its entirety."
