Car exhaust refers to the gases and particles that are emitted from a vehicle's engine during operation. These emissions are a byproduct of the combustion process, where fuel is burned to power the car. The exhaust system, which includes components like the catalytic converter and muffler, helps to reduce harmful pollutants and noise before the gases are released into the atmosphere. The main components of car exhaust include carbon dioxide, nitrogen oxides, and unburned hydrocarbons. While some of these gases are natural byproducts of combustion, others can contribute to air pollution and health issues. Regulations, such as those set by the Environmental Protection Agency (EPA), aim to limit harmful emissions from vehicles to protect the environment and public health.