Car exhaust, also known as exhaust gas or flue gas, is emitted as a result of the combustion of fuels such as gasoline, diesel, or natural gas. It is a mixture of different gases and particles emitted by vehicles when the engine is running. These emissions can include carbon monoxide, carbon dioxide, nitrogen oxides, and hydrocarbons, among others. The primary function of a car exhaust system is to direct all exhaust fumes from the engine to behind the vehicle, reduce emissions by decreasing the number of toxic chemicals in the fumes, and reduce the noise caused by the fuel combustion process