Exhaust gases are the byproducts produced when fuel is burned in engines, such as those found in cars and airplanes. These gases are released into the atmosphere through the exhaust system, which includes components like the exhaust manifold and muffler. Common components of exhaust gases include carbon dioxide, water vapor, nitrogen oxides, and unburned hydrocarbons. The composition of exhaust gases can vary depending on the type of fuel used and the efficiency of the combustion process. Reducing harmful emissions from exhaust gases is important for environmental protection, leading to the development of technologies like catalytic converters and electric vehicles.