Ozone concentrations

N.B. you are viewing the archived 2015 report.

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Key finding

While ozone levels in Townsville and Gladstone have never exceeded air quality standards, South East Queensland experienced exceedences in 2005, 2011 and 2015.

Ozone is a major component of photochemical smog. It is not directly emitted to the atmosphere: it forms when oxides of nitrogen (NOx) and volatile organic compounds (VOCs) react in sunlight. The reaction also forms secondary particles (haze) which can reduce visibility.

The amount of NOx influences the total amount of ozone produced while the VOCs and sunlight influence the rate at which it is produced.

Fuel-burning processes are the major NOx contributors:

  • motor vehicles
  • power stations
  • industrial combustion.

The most significant sources of VOCs are:

  • motor vehicles
  • industry
  • biogenic emissions from vegetation.

While the potential for significant amounts of ozone to be produced only occurs on warm sunny days under light wind conditions, elevated levels of ozone have been observed when bushfires are prevalent in the region.

Ozone is measured in South East Queensland (SEQ), Gladstone and Townsville.

Exceedences of the National Environmental Protection Measures (NEPM) air quality standards have only occurred in SEQ, and only in three years (December 2005, September 2011 and March 2015) in the past decade. The exceedance in 2005 was caused by emissions of precursor pollutants from industry, motor vehicles and domestic sources, coupled with favourable weather conditions for photochemical smog formation. Exceedences in 2011 and 2015 were associated with bushfires. Levels have remained fairly stable over this period with no definite trends. In the previous decade, exceedences occurred on average at least once per year.

Higher temperatures predicted in the future as a result of climate change are likely to increase the potential for ozone formation.

More information:

Indicator: Trends in number of exceedences of NEPM air quality standards for ozone concentrations (smog)

Trends in number of exceedences of National Environmental Protection Measures (NEPM) Air Quality Standards for ozone concentrations (smog) by airshed for the period 2000-2015.

Download data from Queensland Government data