Which component in a vehicle's exhaust system helps to reduce harmful emissions?

The catalytic converter plays a crucial role in a vehicle's exhaust system by converting harmful gases produced during combustion into less harmful emissions before they are released into the atmosphere. It contains catalysts, typically platinum, palladium, and rhodium, that facilitate chemical reactions. These reactions transform carbon monoxide, nitrogen oxides, and unburned hydrocarbons into carbon dioxide, nitrogen, and water vapor, significantly reducing the toxicity of the exhaust gases.

In contrast, the exhaust manifold is primarily responsible for directing exhaust gases from the engine’s cylinders into the exhaust system, while the oxygen sensor monitors the level of oxygen in the exhaust gases to help maintain optimal combustion efficiency, but does not actively reduce emissions. The muffler, on the other hand, mainly serves to reduce noise produced by the engine’s exhaust flow without addressing the chemical composition of the emissions. Therefore, the catalytic converter is essential for minimizing the vehicle's environmental impact by enabling the conversion of harmful substances.