1. Carbon Dioxide (CO2): This is the primary greenhouse gas emitted by internal combustion engines. When hydrocarbons (fuel) react with oxygen during combustion, they produce CO2 and water vapor.
2. Water Vapor (H2O): It is also a product of fuel combustion. The hydrogen atoms in the fuel combine with oxygen to form water vapor.
3. Nitrogen Oxides (NOx): These compounds, including nitric oxide (NO) and nitrogen dioxide (NO2), are formed when nitrogen and oxygen in the air react at high temperatures and pressures inside the engine. NOx contributes to smog and acid rain.
4. Carbon Monoxide (CO): This poisonous gas is produced when there is insufficient oxygen during combustion. CO can lead to health problems such as headaches, dizziness, and even death in high concentrations.
5. Unburned Hydrocarbons (HC): These are partially combusted or unburned fuel molecules that escape from the engine's exhaust. They contribute to smog and can also react with other pollutants to form ozone.
6. Particulate Matter (PM): These are small particles of solid or liquid matter that are emitted from the engine. PM can include soot, ash, and other microscopic particles, and can contribute to respiratory problems.
7. Sulfur Oxides (SOx): These compounds, primarily sulfur dioxide (SO2), are produced when fuel containing sulfur undergoes combustion. SOx contribute to acid rain.
8. Lead (Pb): This heavy metal used to be added to gasoline as an anti-knock agent but has been phased out due to its harmful effects on the environment and human health. However, older vehicles still using leaded fuel can emit lead during combustion.
The specific composition and quantities of these products can vary depending on the type of engine, fuel used, engine operating conditions, and emission control systems in place.
