A little chemistry helps to understand what your Cadillac catalytic converter does - and how important its role in your vehicle's emission system. A catalyst is any substance that causes a change in the rate of a chemical reaction (either to speed it up or to slow it down). Automobile catalytic converters come in two types: oxidation or three-way types. Oxidation catalysts, which are seen in older models, will break down the emissions made of carbon monoxide and hydrocarbons, but they do not take care of particulates and nitrogen oxides. The three-way catalytic converters are in most modern Cadillac models. The name 'three-way' is a reference to the three groups of pollutants that are treated: carbon monoxide, hydrocarbons and nitrogen oxides. A three-way catalytic converter will change the carbon monoxide and hydrocarbons into carbon dioxide and water, while the nitrogen oxides are transformed into nitrogen. In the latter catalyst reaction, the trace elements of platinum and rhodium will separate the nitrogen atoms from the oxygen atoms; the nitrogen atoms then bond together to form their own nitrogen molecules. This is known as the reduction catalyst reaction. A second catalyst reaction, called oxidation, occurs when the palladium and platinum metals accelerate the reaction of the hydrocarbons and carbon monoxide with oxygen, converting them into carbon dioxide and water. By transforming these pollutants into harmless emission matter, your Cadillac catalytic converter helps preserve the environment from stifling smog and poisoning - so make sure you replace your converter with a new, high-quality part bought from our site.