What are the main chemical components released in car exhaust?

The primary chemical components released in car exhaust primarily include carbon dioxide (CO2), water (H2O), and nitrogen oxides (NOx). Car engines combust fuel, which primarily consists of hydrocarbons; during this process, carbon from the fuel combines with oxygen from the air, resulting in the formation of carbon dioxide. Additionally, due to incomplete combustion and high-temperature reactions, nitrogen oxides are formed when nitrogen from the air reacts with oxygen. Water vapor is also produced as a byproduct of the combustion process, contributing to the exhaust.

This combination of substances is key to understanding the environmental impact of vehicle emissions, especially concerning greenhouse gas contributions and air quality issues. The other options list components that may be present in various contexts but do not accurately represent the main outputs of a typical combustion engine exhaust. For example, while oxygen and nitrogen may be components of ambient air, they are not products of engine combustion in significant amounts, and substances like methane (CH4) and ozone (O3) do not primarily come from car exhaust in the context of normal engine operation.