Atmosphere
Queensland's air quality is generally good, with relatively few exceedences of air quality standards recorded in the period 1999-2002. Regionally, the significant issues are sulfur dioxide concentrations in Mount Isa, particulates and photochemical smog in south-east Queensland, and visibility in Mackay. While there were steady increases in greenhouse gas emissions in the transport and stationary energy sectors between 1990 and 1999, livestock emissions were relatively steady, and land clearing emissions fluctuated considerably. In particular:
- Queensland produced the equivalent of 135.2 million tonnes of carbon dioxide in 1999. The main contributors to these emissions were stationary energy (mostly electricity production.37.3%), land clearing and forestry (24.7%), agriculture (18.5%) and transport (11.4%).
- Average carbon dioxide concentrations at Cape Ferguson near Townsville increased from approximately 355 ppm in 1992 to about 370 ppm in 2002. Average methane concentrations increased from around 1670 ppb in 1992 to about 1710 ppb in 2002.
- Stratospheric ozone losses over Queensland are estimated to be 1% a decade.
- Photochemical smog concentrations exceeded Air NEPM standards in south-east Queensland on an average of two days per year between 1999 and 2002.
- Motor vehicle emissions were a major source of smog precursors in south-east Queensland: 62.2% of oxides of nitrogen (NOx) and 22.0% of volatile organic compounds (VOCs). Other main sources included biogenic emissions from vegetation (7.8% of NOx and 61.2% of VOCs), and industry (15.9% of NOx and 4.0% of VOCs).
- Particulate levels in south-east Queensland, Gladstone, Mackay and Townsville (as measured by the 95th percentile 24-hour PM10 concentration) are normally in the range 25.40 µg/m³, below the Air NEPM standard of 50 µg/m³. Exceedences are a result of bushfires, cane burning and dust storms.
- Burning vegetation released 15 640 tonnes of particulate matter (66% of total emissions) in south-east Queensland in 2000, while industry released 4900 tonnes (21%) and motor vehicles released 2250 tonnes (9%). A severe bushfire season in 2000 was the main source of vegetation burning emissions of particulate matter for the year highlighting the way in which air pollution levels can vary according to circumstances.
- Bushfires, cane burning and dust storms were the main causes of poor visibility between 1999 and 2002.
- Visibility fell below the target of 20 km on a number of days during the period 1999.2002 in south-east Queensland and the Gladstone and Mackay regions. How often poor visibility occurred varied each year due to the occurrences of bushfires, cane burning (Mackay only) and dust storms.
- Motor vehicles released 2277 tonnes of benzene (76% of total emissions), 3583 tonnes of toluene (40%) and 1531 tonnes of xylenes (35%) in south-east Queensland in 2000.
- Maximum 24-hour concentrations of benzene were in the range 0.6.1.2 ppb at monitoring sites in Brisbane and Gladstone in the period 2000-02. Maximum toluene concentrations were in the range 4.9.21.5 ppb at Brisbane monitoring sites and 2.5.47.9 ppb at the Gladstone site. Maximum p-xylene levels were in the range 1.8.3.0 ppb at Brisbane monitoring sites.
- Motor vehicles released 417 317 tonnes of carbon monoxide (88.3% of total emissions) in south-east Queensland in 2000. No exceedences of the Air NEPM standard for CO concentrations were recorded in 1999-2002.
- Motor vehicles released 60 579 tonnes of nitrogen oxides (70.9% of anthropogenic emissions) in south-east Queensland in 2000. No exceedences of the Air NEPM standard for NO2 concentrations were recorded in 1999-2002.
- Industrial sources released 18 328 tonnes of sulfur dioxide (75.0% of total emissions) in south-east Queensland in 2000. No exceedences of the Air NEPM standard for SO2 concentrations were recorded in south-east Queensland, Gladstone or Townsville in the period 1999-2002. The Air NEPM was exceeded on an average of 35 days a year in Mount Isa in the same period.
Last updated: 19 May 2004