What can the NPI tell us about air pollution? – An overview of the 2018-19 NPI results

Written by Simon Welchman and Plistina Almeida


The 2018-19 results from the National Pollutant Inventory were released in April this year. This is the 21st annual dataset published by the program managed by the Australian Government’s Department of Agriculture, Water and the Environment.

The National Pollutant Inventory (NPI) is an internet database that provides the community, industry and government with free information about the emissions of 93 substances in Australia. The NPI requires Australian industries to report their annual emissions to air, water and land. The NPI requires data to be gathered on an industry’s use of energy and substances.

In this article, we revisit our 2014 analysis in order to further investigate the information provided by Australian companies on their annual emissions to AIR. We must highlight that the impressions below are restricted to the NPI data reported by facilities (industrial emissions), which does not include emissions from diffuse sources such as: motor vehicles, solid fuel burning (domestic), bushfires and windblown dust.


Overview of the 2018-19 Results

The NPI 2018/19 dataset includes reports from 4,151 facilities, 149 fewer facilities than in 2014. The number of reporting facilities has remained quite stable in the past 12 years, which suggests that the NPI is reaching 100% of facilities that are required to report. The graph below shows the number of reporting facilities by year since the NPI’s inception in 1998/99.


Figure 1 – Number of Reporting Facilities to the NPI along the 21 years of the program

On a state by state basis, the number of reporting facilities in NSW and SA have increased slowly in the last six years, whilst WA and NT have remained relatively static. A noticeable fall in reporting facilities is evident in QLD in 2014/15. Reporting facilities in VIC and TAS have fallen gradually at the same time.

Figure 2 – Number of Reporting Facilities to the NPI along the 21 years of the program per Australian state/territory


At the national level, the apparent stabilisation in the number of reporting facilities may seem counter-intuitive in Australia’s consistently growing economy. It is likely that the relatively static position is due to the shrinking in Australia’s manufacturing sector at the same time as growth in other sectors of the economy. Nonetheless, it is possible that some industries may still not be aware of their reporting requirements. If you are unclear about your reporting obligations, contact us for a free discussion.


Industries that report to NPI

The industry with the greatest number of reporting facilities is Petroleum Product Wholesalers with around 500 facilities. This number has fallen by 5% since 2009. The graph below shows the top 10 industries by the number of reporting facilities.

Sewerage and drainage services have increased by 18% since 2009, which is likely due to population growth. The number of chicken meat farms that report to NPI has fallen by 40%. At the same time, Australia’s chicken meat production has increased by 46% (ACMF 2020). This suggests a consolidation in the industry to larger farms.

Figure 3 – Top 10 ANZSIC class in the past 10 years


How have emissions from petroleum wholesalers and chicken farms changed?

Volatile organic compounds (VOCs) are a group of compounds that are emitted from Petroleum Product Wholesalers. Emissions of total VOCs from Petroleum Product Wholesalers have fallen by 60% since 2009. At the same time, the number of facilities has fallen slightly and fuel usage (petrol plus diesel) has increased with population at about 1.5% per year (Department of the Environment and Energy 2019). Whilst it is unclear how the reduction in emissions has been achieved, there are a range of technologies available that can reduce emissions including:

  • Improved tank technology and maintenance
  • Vapour balancing whereby expelled vapours are captured as a tanker unloads
  • Vapour recovery whereby captured vapours are converted to liquid product.

Figure 4 – Changes in emissions of Total VOCs to Air from Petroleum Product Wholesalers


Ammonia is a key air pollutant that is emitted from chicken meat production. Ammonia emissions from the Poultry Farm Meat industry have reduced by 26% in the past 10 years. At the same time meat production has increased by 46%. It is interesting to note that emissions peaked in 2011/12 and then fell dramatically until 2014/15. From 2014/15 to 2018-19, emissions of ammonia have increased by about 18%. Over the same period, national chicken meat production increased by 9%.

Figure 5 – Changes in emissions of ammonia to Air from Poultry Farms (Meat) in the past 10 years

Trends in emissions of air pollutants

What about the trends in total emissions of air pollutants? Once again, 93 substances are too many to go through individually, so let’s look at the most emitted pollutants.

The ten air pollutants with highest emission rates account for 99% of air pollutant emissions in Australia in 2018-19. This is consistent with previous years. The top ten has been unchanged over the past seven years. The table below shows the top ten air pollutants by total emissions in 2018/19.

Table 1 – Sum of Total Emission to Air from industrial facilities to the 2018/19 NPI displayed in terms of percentage of the total

Minor changes in the ranks of the top 10 pollutants have occurred since 2012/13 (the period since our last article published in 2014). The graph below shows the rankings from 2012/13 and 2018/19.

Figure 6 – Top 10 pollutants to air reported by the most facilities between 2012/13 and 2018/19


Pollutant Highlight

The graph below shows a breakdown of total emissions to air of PM10 in Australia in the past 10 years broken down by State/Territory from NPI facilities. The graph does not include the contribution from motor vehicles, wood heaters, bushfires and other non-industrial activities. Non-industrial activities are significant contributors to PM10 emissions.

Figure 7 – Sum of total emission to air of Particulate Matters (PM10) in kg per State/Territory in the past 10 years from NPI facilities in the past 10 years


Whilst reducing PM10 emissions to zero is difficult, many industries are actively pursuing emission reductions. Key elements of their improvement strategies include:

  • Generating good emissions data through inventory development and NPI reporting
  • Emissions benchmarking
  • Dispersion modelling
  • Cost benefit analysis
  • Improvement strategies.

Meanwhile, Weather Intelligence is helping companies forecast conditions that are high-risk for dust, which allows them to proactively manage their activities to reduce dust emissions and comply with regulatory obligations.

Figure 8 – Sum of total emission to air of Total VOCs in kg per State/Territory in the past 10 years


Figure 9 – Sum of total emission to air of NOx in kg per State/Territory in the past 10 years

How can Katestone help you?

Katestone guides its clients through each step of the NPI reporting process, including data collection, calculation of the emissions inventory, review, comparison with previous years’ inventories and lodgement of the data. Many of Katestone’s clients also elect to receive a succinct reference report that specifies the methodologies used to calculate emissions, the base input data and historical emissions.

Our tailored tools streamline data collection, saving time for our client’s staff and enhancing reliability and accuracy of outputs. Through our diligence, we regularly identify insights that add value to our client’s business outside of the NPI process.

Click here to find our Annual Reporting Capability Statement in PDF.

Notes about this article

Terms of Use: The NPI data is licenced under a Creative Commons Attribution 4.0 International. It’s attributed to the Australian Department of the Environment and Energy and the original version of the data can be found here. No modifications were made to the data, however, filters were applied in order to create graphs and tables to inform our interpretation of the NPI data.

Some of the references used in this article can be found below:

Contact us here to discuss data collection and the lodgement of your 2019/20 NPI report.

This article featured in the Katestone’s Clear Skies 2020 Winter edition. Click here to view other featured articles.

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