About the NPI
Fact sheet
Department of the Environment and Heritage, April 2005
What is diffuse data?
Diffuse data is emissions within airshed and water catchment study areas. Diffuse data includes sources from specific regions. Sources include:
How many regions are there and how were they selected?
There are 33 airshed and 32 water catchment regions, and they include urban and rural locations. The location and size of the regions are determined in line with stakeholder priorities. The regions do not cover the whole country.
Why is diffuse data included in the NPI?
Diffuse data provides a more comprehensive picture of pollution across Australia and provides context for facility emissions.
How do states and territories determine diffuse emissions?
Diffuse manuals are available on the web to assist in identifying the best way of determining the emissions.
How can I be sure that diffuse data is accurate?
State and territory agencies used the best available methods to calculate the diffuse emissions as they became available. Ongoing work is being undertaken to improve the accuracy of diffuse emissions data.
How often is diffuse emissions data updated?
Diffuse data studies are not updated annually, but are likely to be revisited every three to five years. A great deal of planning, effort and expense goes into these studies and it is not practical or necessary to update the data more frequently.
Can meaningful comparisons be made between diffuse data from different jurisdictions?
Currently, care is needed in comparing diffuse data between airsheds and between water catchments. Data collection is at an early stage and some consistency issues need to be addressed.
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