What is a catalytic converter used for in vehicles?

A catalytic converter plays a crucial role in reducing the environmental impact of vehicles by converting harmful gases produced during combustion into less harmful emissions. Specifically, it facilitates chemical reactions that transform carbon monoxide, nitrogen oxides, and unburned hydrocarbons—common pollutants from vehicle exhaust—into carbon dioxide and nitrogen. This process significantly improves air quality by minimizing the number of toxic substances released into the atmosphere.

While there are components in a vehicle that can enhance engine performance or increase fuel economy, these functions are not the primary purpose of a catalytic converter. Additionally, although catalytic converters can have a minor effect on engine noise levels due to their structure and placement in the exhaust system, their main function is focused on emissions reduction, which makes the second option the correct answer.