Knowra Vehicle emissions Vehicle emissions Vehicle emissions are gases and particles released by motor vehicles during fuel combustion and operation. Their composition depends on the vehicle, fuel, engine, and emissions-control systems.
Internal combustion engine : An engine that produces mechanical power by burning fuel inside its cylinders or combustion chambers. Combustion inside these engines generates many exhaust pollutants.
Carbon monoxide : A colorless, odorless, poisonous gas produced by incomplete combustion of carbon-containing fuels. It is a major toxic component of exhaust from gasoline engines.
Air pollution : The presence of substances in air at concentrations that harm health, ecosystems, or materials. Vehicle emissions are one source of this broader environmental problem.
Vehicle emissions testing : Procedures that measure or assess pollutants released by vehicles under specified conditions. Testing checks whether vehicles meet limits and whether controls still function.
Zero-emission vehicle : A vehicle classified by a jurisdiction or standard as producing no regulated emissions during operation. It contrasts with combustion vehicles, though definitions may exclude upstream energy emissions.
Combustion : A chemical reaction in which a fuel reacts with an oxidizer, releasing heat and often light. Incomplete combustion produces carbon monoxide, hydrocarbons, and soot.
Nitrogen oxides : A group of reactive gases, chiefly nitric oxide and nitrogen dioxide, formed during high-temperature combustion. High combustion temperatures create these pollutants, especially in engines.
Ground-level ozone : A harmful air pollutant formed near the ground through sunlight-driven reactions involving nitrogen oxides and volatile organic compounds. Vehicle pollutants help form ozone in sunlight rather than emitting it directly.
Emission standard : A regulatory limit on the amount of a pollutant that a source may emit. Standards set legal ceilings for pollutants from vehicles.
Hybrid electric vehicle : A vehicle that combines an internal combustion engine with an electric motor and energy storage. Its fuel use and tailpipe emissions can be lower than those of a comparable conventional vehicle.
Show all 30