How Catalytic Converters Reduce Vehicle Emissions
Launch library · evergreen read
A catalytic converter sits in a vehicle's exhaust system and uses precious metal coated surfaces to speed up chemical reactions that would otherwise happen too slowly to matter. As exhaust gases pass through, carbon monoxide and unburned hydrocarbons are converted into carbon dioxide and water vapour.
At the same time, a separate part of the reaction reduces nitrogen oxides back into harmless nitrogen and oxygen gas. This combination of oxidation and reduction reactions, happening within the same compact device, is why a single converter can address several different pollutants from one exhaust stream.
The technology does not eliminate carbon dioxide, since that is the natural byproduct of burning fuel, but it substantially cuts the pollutants most directly linked to smog and respiratory irritation. That distinction matters when comparing emissions technologies, since reducing local air pollution and reducing greenhouse gases are related but separate goals. A vehicle can therefore pass an emissions test focused on local air pollutants while still contributing meaningfully to overall carbon output through its fuel use.