Impact of cars on the environment

Air Quality

While it's true that Perth's air is relatively clean at present, air pollution levels are only just below threshold levels and constant vigilance is required to prevent them becoming too high.

Motor vehicle use generates over half of the air pollutants in Perth. Responsible use of our cars is therefore essential to keep Perth's air clean.

An Australian Bureau of Statistics survey of motor vehicles in Australia showed that 25% of households serviced their vehicles once a year or less. The manufacturer's recommendation is normally every six months or 10,000kms. This means that at least a quarter of the vehicles on our roads are under-serviced and therefore generating more than their fair share of emissions. If your car is one of those not properly tuned and maintained, its contribution to Perth's pollution levels could be excessive.

As the number and age of vehicles on our roads increases, the importance of regular maintenance in keeping emissions down also increases.

Motor vehicle use is a major contributor to the pollution of Perth's air. The Perth Photochemical Smog Study showed that motor vehicles contribute 51% of nitrogen oxide emissions and 44% of hydrocarbon emissions.

Nitrogen oxides and hydrocarbons also react together to produce ozone, which at ground level is a pollutant. Perth's ozone levels are only just below maximum levels in summer.

Particulates are also becoming a cause for concern. Increases in the number of diesel-fuelled vehicles will increase the emissions of particulates.

While atmospheric nitrogen dioxide and carbon monoxide levels are not a problem at present, as Perth grows in size, congestion will increase along with the number of kilometres travelled. This will increase the volume of emissions produced. The net result will be to increase the pollution load on Perth's air shed.

Greenhouse gases

The major greenhouse gas emitted by cars is carbon dioxide. Carbon dioxide in the atmosphere traps heat from the sun and prevents it from being re-emitted back into space. The natural background level keeps the average temperature of the planet at a liveable level. However it is a very delicate balance between the carbon dioxide levels in the atmosphere and the amount of heat retained. An increase in carbon dioxide levels will cause the planet to heat up. Other greenhouse gases include nitrous oxide and methane.

Human activities over the past 200 years have caused the amount of carbon dioxide in the air to increase by 30%. It is becoming more and more apparent that this will lead to an increase in the average temperature of the Earth. The consequences of this are not really known but it now seems likely that they will be disruptive to our lives. It is therefore important to minimise our carbon dioxide and other greenhouse gas emissions and prevent background levels rising to dangerous levels.

Approximately 8% of Australia's carbon dioxide emissions are from cars and light commercial vehicles which is why reducing our emissions from car use is vital. Carbon dioxide emissions are directly tied to fuel use so it is important to minimise the amount of fuel consumed. For every litre of petrol used, 2.3 kg of carbon dioxide is emitted into the atmosphere. The average passenger vehicle emits about four tonnes of carbon dioxide each year.

Noise

Vehicles affect the environment by creating noise:

• In urban environments, road traffic is the most important single source of community noise.
• Noise can cause or bring about disturbance to work, relaxation and sleep; mental stress; and in severe cases physical problems such as chronic exhaustion, high blood pressure and heart disease.
• Noise from motor vehicles increases with the size and speed of the vehicle. Vehicle and tyre design and vehicle maintenance also affect noise levels.

Ozone depletion

Australian legislation bans the manufacture and importation of chlorofluorocarbons (CFCs), an ozone depleting substance that was once widely used in car air-conditioners. Their replacement gases, hydrofluorocarbons (HFCs) and hydrocarbons (HCs) do not damage the ozone layer. They do, however, have a greenhouse effect. To avoid leaks of air-conditioning gases, keep units maintained and follow instructions in the owner's manual.

Ozone in the upper atmosphere protects life on earth by absorbing ultraviolet (UV) radiation from the Sun. UV radiation is linked to skin cancer, genetic damage and immune system suppression as well as reduced productivity in agricultural crops.

Water quality

Vehicles affect water quality because oil and particles run-off from roads into stormwater drains. These feed into creeks and rivers, which eventually meet the sea.

Their are a number of pollutants that affect water quality. Oil is a particularly harmful water pollutant. Even a small amount of oil can severely contaminate waterways. Oil can be toxic to aquatic life and smother plants and animals; Particles from the wear of tyres, brakes and other components get washed into the stormwater and pollute waterways; When it rains, air pollution from cars mixes with rainwater and falls to the ground, adding to water pollution; as well as detergents.

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