Does the Ambient Air Quality NEPM Update apply to your application?

On 15 April 2021, the National Environment Protection Council (NEPC) approved the variation to the Ambient Air Quality National Environment Protection Measure (AAQ NEPM or Air NEPM) standards for ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2).  The variation tightens standards that have been in place for 23 years.


In 1998, the Air NEPM established national standards for six criteria pollutants and a consistent Australia-wide framework for monitoring and reporting ambient air quality by state and territory governments.


The desired outcome of the Air NEPM has also been amended from ambient air quality that allows for the adequate protection of human health and wellbeing to focus on minimising health risks associated with air pollution exposure. Besides that, the Air NEPM ultimate goal is compliance with air quality standards.


Here are some key changes that you might be interested in:

Significantly lower NO2 standards:

  • The 1-hour average standard is 25% lower than existing standard
  • The annual average standard is 50% lower than existing standard
  • No proposed change to these standards beyond 2025.

Significantly lower SO2 standards:

  • The 1-hour average standard is 50% lower than existing standard
  • The 1-day average standard is 75% lower than existing standard
  • The annual average standard has been removed
  • By 2025, the 1-hour average standard will be further reduced by 63% compared to the existing standard.

Significantly changed O3 standards:

  • The 1-hour and 4-hour average standards have been removed.
  • An 8-hour standard of 65 ppb has been established.


A summary of the Air NEPM reviews can be found in the table below:

Table 1             Standards for pollutants with changes (ppb)

Pollutant Averaging period Current Air NEPM (ppb) Proposed Air NEPM (ppb)
New Standard 2025 goal
Nitrogen dioxide 1 hour 120 80 80
1 year 30 15 15
Sulfur dioxide 1 hour 200 100 75
1 day 80 20 20
1 year 20 Removed
Photochemical oxidants (as ozone) 1 hour 100 Removed
4 hour 80 Removed
8 hour N/A 65* 65

There are no exceedances of any of these standards allowed under the Air NEPM

* For ozone, apply the exceptional rule that applies to particles given the linkages between O3 levels and fire events

What does it mean to your operations?

The revised Air NEPM has most immediate implications for state and territory governments, which will be required to report against the new standards.  They will also need to consider how the revised standards should be accounted for in each jurisdiction.  A number of jurisdictions have already signalled that the revised standards will be adopted as planning and assessment criteria.  There is also likely to be strong interest from the community that the revised standards should be applied to existing industry.


The standards in the AAQ NEPM are not intended to be applied as environmental standards by regulators without consideration of regulatory impacts in their jurisdictions. The Explanatory Statement clarifies this intent of the Air NEPM as a standard for reporting representative ambient air quality within an airshed, and not as a regulatory standard.


However, the Air NEPM standards have previously been adopted in each jurisdiction as environmental standards for assessment and design of new and existing industries.  It is, therefore, likely that air quality assessments that are conducted for new facilities or for amendments to existing facilities will need to account for the revised Air NEPM standards.  Indeed, Katestone is aware that a number of jurisdictions have already signalled their intention to adopt the revised standards in their air policies and modelling guidelines.  Katestone is also aware that the Air NEPM standards have been used for the assessment of a number of industrial developments throughout Australia.


The motivation behind the changes

NEPC’s review of standards for ozone, nitrogen dioxide and sulfur dioxide took account of the recent evidence of health effects of these pollutants. In particular, the impact statement on the proposed variation to the Air NEPM considered:

  • the feasibility of updating the standards
  • the costs and benefits of a range of potential abatement measures that could be introduced to lower concentrations for these pollutants
  • the form of revised standards (for example averaging periods)
  • the merits of introducing an exposure reduction framework for these pollutants to continue to reduce population exposure and health risk
  • whether an exceptional events rule should be introduced for these pollutants
  • modernising the outcome and goal of the AAQ NEPM
  • changes to clause 14 of the AAQ NEPM (the number of performance monitoring stations) and some additional definitions to provide a primary focus on risk while still preserving the population threshold and formula.


A central component of the Air NEPM Review Impact Assessment was the future projection of air quality against the proposed air quality standards and goals. Future projections of air quality were determined for specific years (2016, 2021, 2031 and 2040). The projections were based primarily on future emissions estimated by the 2008 NSW Greater Metropolitan Region (GMR) inventory and the 2006 Victorian Inventory with adjustment for recent changes in legislation and known facility closures.

How can Katestone help you?

Katestone’s fit-for-purpose studies have supported numerous proposed industrial, infrastructure and agricultural developments. Katestone has assisted its clients to reduce emissions whilst improving operations and mitigating operational risks. We assist our clients with the management of air quality, odour, greenhouse gas emissions and climate change associated with planned or existing operations.


Our clients benefit from studies that quantify the potential impacts on air quality across the lifetime of a project. We have also contributed significantly to the development of air quality management policies and legislation throughout Australia by conducting targeted research and analysis.


References 2021. [online] Available at: <> [Accessed 5 August 2021]. 2021. [online] Available at: <> [Accessed 5 August 2021]. 2021. [online] Available at: <> [Accessed 5 August 2021].


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This article featured in the Katestone’s Clear Skies 2021 Winter edition. Click here to view other featured articles.

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