Car exhaust gases contain hydrocarbons, nitrogen oxides, carbon dioxide
carbon monoxide, sulphur dioxide, carbon particles, fine particulate matter and small amounts of aromatic hydrocarbons (benzene) and dioxins. They used to also contain lead.
Car exhaust gases are highly toxic because of their carbon monoxide content. Many people have been killed by exhaust gases leaking into the inside of cars. The first signs of poisoning are drowsiness, followed by unconsciousness, then death. Never run a car engine in a closed garage! A large part of air pollution in cities comes from car exhaust. One form of air pollution is formed when, under the action of sunlight, the nitrogen oxides react with the hydrocarbons to form photochemical smog and ozone. This can precipitate or exacerbate asthma in sensitive people. Air pollution has been linked with various respiratory illnesses, heart disease and lung cancer. See also entries for the specific chemicals.
Car exhaust gases contribute to air pollution, the greenhouse effect and acid rain. In Australia, new cars sold since 1986 are fitted with catalytic converters which convert partly burnt fuel and carbon monoxide into carbon dioxide and water. Unleaded petrol must be used in such cars as lead will cause permanent damage to the catalytic device. Many new Australian cars are already fitted with 'triple converters' which are designed to reduce the emission of nitrogen oxides as well as that of the other pollutants.
To reduce pollution and save energy:
- Walk, cycle or use public transport.
- Form a car pool.
- Use the smallest practical car and engine to fulfil your needs.
- Make sure your motor vehicle runs efficiently, especially if it has a diesel engine. Diesel engines emit large quantities of air pollutants if poorly tuned. Consider biodiesel if you run a diesel vehicle (see www.biodiesel.org.au for more information).
- Avoid excessive speeds and heavy braking, which both waste fuel.
- Keep tyres at the correct pressure and remove roof rack when not in use.
- Use a car fitted with an emission control catalyst.
Car manufacturers are also working on new types of motors and energy sources to reduce emissions and fossil fuel use, although it may be some time before they are widely available. These include solar and hydrogen power (see also Motor fuel ).