Standards and goals for measuring air pollution

Setting air quality standards and goals are essential for protecting human health and the environment from the adverse effects of air pollution.

High concentrations of the major air pollutants are associated with respiratory problems such as coughs, bronchitis, asthma and, in severe cases, developmental problems in children, and even death. 

The National Environment Protection Measure for Ambient Air (Air NEPM) sets national standards for the six key air pollutants to which most Australians are exposed: carbon monoxide, ozone, sulfur dioxide, nitrogen dioxide, lead and particles.

Standards refer to maximum concentrations of the pollutants set by Air NEPM. Goals refer to allowable exceedances of these maximum concentrations during a year. Find out what these goals and standards are in the table below.

On 15 April 2021, the National Environment Protection Council varied the AAQ NEPM standards for ozone, nitrogen dioxide and sulfur dioxide. The variation resulted from a national review of standards for these pollutants, considering the latest scientific evidence about health impacts of air pollution. The revised standards were legislated on 18 May 2021 (Schedule 2). The table below states these current standards. Note that there are no maximum allowable exceedances for any pollutants, including for particles as PM10, particles as PM2.5, and ozone (after excluding exceptional event days). In the same table, the standard for visibility (or NEPH) is set for NSW by the Department of Climate Change, Energy, the Environment and Water.

The practical adoption of these revised standards to live data reporting in New South Wales is in progress. In the transitional stage, the previous 2015 AAQ NEPM standards will apply for the 2021 reporting year, until the full reporting system is upgraded by early 2022.

Standards and goals


Averaging period

Maximum concentration or standard

Carbon monoxide

8 hours

9.0 ppm

Nitrogen dioxide

1 hour

1 year

0.08 ppm (8 pphm)

0.015 ppm (1.5 pphm)

Photochemical oxidants as ozone 

8 hours

0.065 ppm (6.5 pphm)

Sulfur dioxide

1 hour

1 day

0.10 ppm (10 pphm)

0.02 ppm (2 pphm)

 Lead 1 year
0.50 µg/m3

Particles as PM10

1 day

1 year

50 µg/m3

25 µg/m3

 Particles as PM2.5

1 day

1 year

25 µg/m3

8 µg/m3

Visibility or NEPH (as bsp)

1 hour

3 x 10-4 m-1 (300 Mm-1)


parts per million by volume (that is, parts of pollutant per million parts of air). To convert to reported units of pphm multiply by 100.
 pphm =
parts per hundred million by volume (that is, parts of pollutant per hundred million parts of air). To convert to ppm, divide by 100.
particulate matter less than 10 micrometres in diameter
= particulate matter less than 2.5 micrometres in diameter
= micrograms per cubic metre, referenced to a temperature of 0° Celsius and an absolute pressure of 101.325 kilopascals.

back scattering potential, which represents the coefficient of light scattering due to particles and is a measure of visibility reducing particles. The lower the bsp value, the lower the level of suspended particles and the better the visibility.

There is no AAQ NEPM standard or goal for visibility. The value of 210 Mm-1 (inverse megametres) was the NSW adopted 1 hour standard before November 2020, after which 300Mm-1 was adopted as the current NSW 1 hour standard.

Exceptional event

means a fire or dust occurrence that adversely affects air quality at a particular location that is directly related to bushfire, jurisdiction authorised hazard reduction burning or continental scale windblown dust, and that causes an exceedance of one or more of the following that is in excess of normal historical fluctuations and background levels:

  1. 1 day average standard for particles as PM10
  2. 1 day average standard for particles as PM2.5
  3. 8 hour average standard for photochemical oxidants (as ozone)

When reporting compliance against NEPM goals for both PM10 and PM2.5 daily averages and photochemical oxidants (as ozone) 8-hour average standards, any exceedance day deemed to be impacted by an exceptional event is excluded and classified as an exceptional event day. Where an exceedance day is determined to be impacted by a non-exceptional event, it is included  and classified as a non-exceptional event day.