Melbourne's air quality

Melbourne's air quality has improved since the 1980s. In an international context (compared to similar urban centres) Melbourne's air quality is relatively good. Particle pollution is currently the major air quality issue needing attention. With air quality consistently ranked by the community as an important environmental issue, now is the time to act to protect our community's health and wellbeing.

Measuring the improvement

When EPA began air monitoring in Melbourne and Geelong in 1973, air pollution was getting worse. We saw significant improvements in the following two decades largely due to industry complying with EPA standards and the introduction of emission controls on cars. Over the past decade or so, improvements have been less dramatic, but carbon monoxide (CO) and nitrogen dioxide (NO₂) have continued to decrease. The removal of lead from petrol has caused a dramatic drop in lead levels. Of course pollution levels will vary from year to year because of changes in the weather.

When pollution builds up

Melbourne has three dominant forms of air pollution:

1. The first is when fine particles and other pollutants build up in stable atmospheric conditions.

   This usually occurs in autumn and winter during windless days and nights when pollution from solid fuel heating (wood heaters and open fireplaces) and motor vehicles accumulates in the atmosphere.

   Temperature inversions in winter mean that warm air higher in the atmosphere traps pollutants in the layer of cold air closer to the ground. These inversions can last for several days and cause 'scummy' brown hazed horizons until dispersed by wind or rain.

   Recent research shows these microscopic particles in the air may cause breathing difficulties and exacerbate respiratory problems for the elderly and asthmatics. Some of these particles also contain known carcinogens.

2. Melbourne's second major pollution problem is windborne dust. In high winds dust can be transported long distances, for example, from erosion in the Mallee or Wimmera. Dust from nearby earthworks can also be a local problem in windy conditions.

3. Thirdly, sometimes winds cause the pollutants to be recirculated around the Port Phillip region. As the smog levels build, polluted air from Melbourne can be returned, typically on a sea breeze. This means that in the evening you can end up breathing exhaust fumes emitted by your car that morning. In strong sunlight, photochemical reactions can create high levels of ozone. This is called a summer smog event.

Sources of pollution

You may be surprised to learn that the biggest polluter of our air is not industry, but motor vehicles, which are responsible for about half of Melbourne's air pollution in summer.

Get more information about motor vehicle emissions (including how you can make a difference).

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How you can make a difference every day

Most of us are probably causing air pollution in one way or another, but the good news is that we can all do something as individuals to reduce emissions every day. Some require more commitment than others but for each of us there's a way to play our part and make a difference.

1. Keep your car regularly tuned and maintained and cut car pollution by up to 25 per cent - and you'll also save on fuel consumption.
2. Drive smoothly and plan your trips - you'll arrive just as quickly and save more on fuel.
3. Keep your car's tyres inflated to the manufacturer's specifications.
4. Try riding a bike or walking instead of using a car.
5. Use public transport wherever you can.
6. When you trade in your old car check out the possibility of sharp, snappy, fuel-efficient, low emission car as a replacement.
7. Limit your wood fireplaces to romantic weekends or special occasions.
8. Report smoky vehicles.

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