Catalytic Converter

Catalytic Converter, device incorporated into the exhaust system of an automobile that reduces the amount of pollutants in the automobile's exhaust gases. A catalytic converter contains small beads that are coated with metals, such as palladium and platinum. When exhaust gases pass through the catalytic converter, these metals act as catalysts, encouraging chemical reactions that change pollutants, such as carbon monoxide and certain hydrocarbons, into less harmful carbon dioxide and water (see Catalysis). Lead-free gasoline must be used in automobiles that have catalytic converters; otherwise, the beads in the catalytic converter will become coated with lead and cease to function properly. Since the 1970s, state and national governments in the United States have passed increasingly stringent emission-control measures. To meet these emission standards, since the early 1980s, all new cars sold in the United States have been equipped with catalytic converters.