NOVELTY - A supported catalyst particle comprises catalyst particles supported in and/or on particles of electrically conductive support selected from graphitic carbon and a partially reduced oxide.    USE - As supported catalyst particles for making a cigarette; for oxidizing carbon monoxide to carbon dioxide; in tobacco cut filler, cigarette wrapper and/or cigarette filter of a cigarette (claimed); for low-temperature and near-ambient temperature catalysis of carbon monoxide and/or nitric oxide; in hydrocarbon conversion reactor to convert hydrocarbons; in vehicle exhaust emission system to oxidize carbon monoxide to carbon dioxide; for emission reduction in the cold starting of automobile engine; in laser; in fuel cell; and in air filter for conversion of carbon monoxide and/or indoor volatile organic compounds.    ADVANTAGE - The particle reduces the amount of carbon monoxide and/or nitric oxide in smoke; and effectively converts carbon monoxide to carbon dioxide and/or convert nitric oxide to nitrogen during smoking of the cigarette. The supported catalyst particles also reduce the concentration in mainstream smoke of at least one polyaromatic hydrocarbon compound such as naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthrene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthrene, benzo(k)fluoranthrene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenz(a,h)anthracene and benzo(g,h,i)perylene.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a method of making a cigarette involving: incorporating supported catalyst particles in and/or on at least one of tobacco cut filler, a cigarette wrapper optionally comprising web-filler material and a cigarette filter comprising filter material, where the supported catalyst particles comprise catalyst particles supported in and/or on support particles; forming a tobacco column from the tobacco cut filler in a cigarette making machine; placing the cigarette wrapper around the tobacco column to form a tobacco rod of a cigarette; and optionally attaching the cigarette filter to the tobacco column using tipping paper; and    (2) a method of oxidizing carbon monoxide to carbon dioxide involving contacting catalyst particles supported in and/or on electrically conductive support particles of graphitic carbon or a partially reduced oxide with a gas containing carbon monoxide, where the gas is selected from mainstream and/or side-stream cigarette smoke, vehicle exhaust emission, a gas used in a laser, a gas used in a fuel cell, and ambient air undergoing air filtration.