Is Australia’s measure of sulphur dioxide pollution 11 times weaker than the World Health Organisation standard and weaker than the EU, US and China?

By James Lane and Tiffanie Turnbull

The Statement

"The Australian standard for SO2 pollution is 11 times weaker than those recommended by the WHO, and weaker than levels set by the EU, US and China."

Nature Conservation Council of NSW CEO Kate Smolski. May 24, 2019.

The Analysis

The Nature Conservation Council of NSW conducted an analysis of Office of Environment and Heritage air quality data for parts of Sydney, Newcastle and the Hunter Valley over four years from May 2015 to May this year. The data found sulphur dioxide (SO2) levels exceeded World Health Organisation (WHO) standards 180 times in suburbs around Newcastle.

AAP FactCheck examined the claim by Nature Conservation Council CEO Kate Smolski that Australia’s standard for SO2 pollution is 11 times weaker than the WHO’s measure and weaker than levels set in the European Union, the United States and China. [1]

Sulphur dioxide is a gas which has a sharp smell. About 99 per cent of the sulphur dioxide in air comes from human sources. The main sources of SO2 are industrial activity that process materials containing sulphur such as electricity generation from coal, oil or gas and motor vehicle emissions. Some mineral ores also contain sulphur and SO2 is released when they are processed.

SO2 in the air can in mild cases induce headaches and create breathing difficulties, irritating the nose, throat and airways. Long term exposure can result in lung disease and premature death. [2][3]

The national air quality standard to measure sulphur dioxide concentration dates back to 1998 under the National Environment and Protection Measure for Ambient Air Quality, according a the Department of Environment and Energy fact sheet dated 2005. [4][5]

National air quality standards to measure sulphur dioxide concentration and averaging are: 0.20 ppm (parts per million) averaged over a one hour period; 0.08 ppm averaged over a 24 hour period and 0.02 ppm averaged over a one year period. [4]

The World Health Organisation’s sulphur dioxide standard is 20 micrograms per cubic metre averaged over a 24-hour period. [6]

The concentration of pollutants in air depends on the temperature and air pressure. WHO air quality guidelines reference a temperature of 25C and an air pressure of 101.3 kilopascals. [3][7]

Considering the same conditions and converting Australia’s limit to a like measurement by applying a factor of 26.2 devised by the NSW Office of Environment and Heritage, Australia’s limit amounts to 209.6 micrograms per cubic metre. Australia’s limit is more than 10 times greater than WHO’s limit of 20 micrograms per cubic metre. [3][9]

Regarding the claim comparing EU, US and Chinese standards, the Nature Conservation Council provided AAP FactCheck with several references. The EU claim was based on a UK report for a 24-hour standard for SO2 in Europe and used a WHO conversion factor. For the US an SO2 standard for California was provided as President Donald Trump “dumped the national standard recently”. China has three standards for areas defined as “sensitive, residential, and industrial”. The Nature Conservation Council used the residential measure.

AAP FactCheck concludes that only the claim for Newcastle and the Hunter can be verified and only by data supplied by the Nature Conservation Council.

The Verdict

  • Somewhat True - Mostly accurate, but there is more than one error or problem.

The References

1. ‘Newcastle and the Hunter exceed World Health Organisation standards for sulphur-dioxide pollution over four-year test’, by Simon McCarthy. The Newcastle Herald. May 24, 2019:

2. ‘Sulphur dioxide (SO2)’. Department of the Environment and Energy. Australian Government. 2005:

3. ‘WHO Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide. Global update 2005. Summary of risk assessment’. (Sulfur dioxide page 18) World Health Organization. 2005:

4. National standards for criteria air pollutants 1 in Australia’. Department of the Environment and Energy. Australian Government. 2005:

5. ‘National Environment Protection (Ambient Air Quality) Measure. Federal Register of Legislation’. Australian Government. July 2003:

6. ‘Ambient (outdoor) air quality and health’. World Health Organization. May 2, 2018:

7. ‘Understanding Units of Measurement’. by Terrie K. Boguski. Center for Hazardous Substance Research, Kansas State University. October 2006:

8. ‘Conversion Factors Between ppb and µg m-3 and ppm and mgm-3’. UK Air Information Resource - Department for Environment Food & Rural Affairs. August 2014:

9. ‘Air pollutant units and conversion factors’. NSW Office of Environment and Heritage. February 2019:

  • First published May 27, 2019 13:31 AEST