1. Hydrocarbon (HC):-They play an important role in forming NO2 and O3 which are health and environmental hazard.
2. Carbon Monoxide (CO): CO is a highly poisonous gas that can cause dizziness, headaches, impaired thinking, and death by02 starvation. It can affect the central nervous system, impairing physical coordination, vision and judgment, creating nausea and headaches, reducing worker productivity and increasing personal discomfort.
3. Carbon dioxide: CO2 is a greenhouse gas and may be the major cause of global warming.
4. Oxides of Nitrogen: NO is unhealthy and contributes to the greenhouse effect, NO2 is a very toxic gas and contributes to the formation of smog, ozone, and acid rain.