Perth air emissions study 2011–12

The goal of the Perth air emissions study 2011–12 was to quantify the most significant emission sources in Perth.
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Air quality in Perth is influenced by a range of emission sources.

Naturally occurring emissions from vegetation, soils and the ocean combine with man-made emissions from commercial and industrial facilities, transportation and domestic sources to make up Perth’s air emissions profile.

Read more about the study below.

What is an air emissions inventory?

An air emissions inventory estimates what emissions are produced in an area over a year.

The Perth air emissions study 2011–12 covered the Perth metropolitan area and surrounds between Two Rocks, Toodyay and Waroona.

Emissions have been estimated from:

  • natural sources
  • domestic sources
  • commercial and industrial facilities
  • road vehicles
  • boating and shipping
  • rail and aircraft operations.

All emission estimates are mapped to their source, allowing high emission areas to be identified.

Why have an air emissions inventory?

An air emissions inventory is an important tool for identifying significant pollution sources and gaining a better understanding of air pollution issues in an area.

In many cases, major emission sources are regulated and understood by policy makers. An air emissions inventory helps place these sources in the context of all other emission sources in an area.

An air emissions inventory also provides useful information for further air quality management actions, such as modelling emission dispersion in the atmosphere and identifying locations for air monitoring stations.

How were emissions estimated?

For the study, air emissions were estimated by combining activity data with scientifically developed emission factors. Activity data were sourced from state and national government databases, and directly from industry by way of targeted surveys.

Natural emissions were estimated using established vegetation and geological databases.

Several domestic emission estimates were made using 2011 Australian census data.

Commercial and industrial emission estimates were sourced from the National Pollutant Inventory database and combined with the results of an industry survey of Perth businesses.

Vehicle emission estimates were developed using traffic monitoring data from Main Roads WA and a vehicle emissions model.

Five accompanying technical reports detail the emission estimation methods and activity data. You can view the individual technical reports and a summary report below.

How were emissions assessed?

Emissions for 78 different substances were estimated for the study. All the substances are toxic to some extent, but some substances are more toxic than others. This inventory used a scoring method called toxic equivalency potential (TEP) to assess emission estimates equally.

TEP assigns a score to all emission estimates based on their toxicity and risk to human health. This allows emission sources to be compared against each other, even if they emit different substances.

In addition to TEP scoring, several key substances were individually assessed. These included:

  • carbon monoxide
  • oxides of nitrogen
  • particulate matter (PM10 and PM2.5)
  • sulfur dioxide
  • volatile organic compounds.

Pollutant fact sheets for each substance and TEP have been prepared and show the significant sources and areas where these emissions occur. You can view the fact sheets below.