Emissions control device, incorporated into an automobile’s exhaust system,
that reduce the levels of hydrocarbons (HC), carbon monoxide (CO), and - in more
recent designs - nitrogen oxides (NOx) emitted to the air by gasoline-powered
Catalytic converters do not help reducing emissions during the first minutes
after cold-start, as they need a high temperature to operate.
Français: Convertisseur catalytique