U.S. Patent 7,569,510 assigned to Philip Morris USA, Richmond, Virginia, USA. Catalysts for the conversion, or oxidation, of carbon monoxide to carbon dioxide. Cigarettes with filters containing the catalysts have acceptable resistance to draw. Additionally, the catalysts can be used to reduce the concentration of carbon monoxide from a vehicle exhaust emission, a gas used in a CO₂ laser, a gas used in a fuel cell and/or ambient air undergoing air filtration.