Air Quality

Australia State of the Environment Report 2001 fact sheet
Department of the Environment and Heritage, February 2002

What is happening overall?

The quality of urban air has generally improved or remained constant for most years, but emissions of pollutants in cities, mainly from vehicles remains of concern. Since 1996 Australian governments have introduced ways to improve the health and understanding of the atmosphere.

What is being done to improve air quality?

Governments have agreed a set of air quality standards and a goal of meeting these standards no later than 2008. However, available air quality data indicate that the standards have been met with few exceptions in most urban and regional areas since 1997. This can be attributed to the substantial efforts to reduce pollution from vehicles and major industrial sources.

How do we measure air quality?

Scientists use particles to assess air quality. Particles float in the air and are very small - less than 1/20th the diameter of the average human hair. There are many types of particles in the atmosphere. The very small (or fine) particles are of most concern to human health because they can be inhaled deeply into the lungs.

Why are particles and air quality important?

Particles can exacerbate respiratory and cardiovascular illnesses, such as bronchitis, pneumonia and asthma, that can lead to increased hospital admissions and emergency room visits. Particles have also been linked to deaths. Up to 2,400 deaths a year in Australia are estimated to be linked to particles, with an associated health cost of $17.2 billion.

Where do particles come from?

A wide range of human activities generates particles in urban and rural areas. They include combustion, mechanical and photochemical processes.

The coarser (or larger) particles tend to be produced through mechanical processes, such as wind erosion, mining and minerals processing. Finer particles tend to be combustion-derived, for example motor vehicle exhaust (mainly diesel vehicles), wood combustion, motorised garden equipment and power generation. Tiny secondary particles are formed by the transformation of gaseous pollutants, such as nitrogen oxides and hydrocarbons, through photochemical reactions in the atmosphere.

There are also a number of important natural sources of particles. These include sea salt, dust, emissions from vegetation, pollen and bushfires.

In Sydney, Melbourne, Brisbane and Adelaide, the main sources of particles during winter are combustion and mechanical processes, whereas in areas such as Canberra and Launceston, the main source of particles is combustion, mainly wood burning for heating.

Particle levels vary on a seasonal basis. Woodsmoke can significantly increase particle levels during the cooler months across southern Australia, with increased secondary particle formation occurring during warmer periods.

Bushfires, such as those near Sydney in 1997, or hazard reduction burns on the outskirts of urban areas can significantly increase particle levels. In Perth, the typical source contribution of particles varies with each season. Much of the time smoke from industrial or residential combustion is the dominant source. However, during certain seasons other processes may dominate, for example, windblown soil.

Climate and topographical conditions significantly influence particle levels in rural and regional Australia. In warmer regions, dry conditions contribute to bushfires, and windblown dust. In cooler regions, the widespread use of domestic wood fires for heating can lead to high levels of particles.

What are we doing to manage particles that affect air quality?

Because particles can damage human health, steps have been taken to reduce particle levels in Australia. These include:

  • legislating higher fuel quality standards and setting stricter emission standards for motor vehicles;
  • setting a national ambient air quality standard for particles under the National Environment Protection Measure for Ambient Air Quality (Air NEPM);
  • imposing tighter emission standards for new wood heaters and providing educational materials on their correct operation;
  • implementing the Australian Minerals Industry Code for Environmental Management to reduce dust emissions from mining areas; and
  • encouraging better coordination between responsible authorities to limit air pollution from essential hazard reduction burns.