4613.0 - Australia's Environment: Issues and Trends, 2007  
Previous ISSUE Released at 11:30 AM (CANBERRA TIME) 11/01/2008   
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Contents >> Atmosphere trends >> Air quality

Image: Smoke stacksAIR QUALITY


Particulate concentrations, PM
10
Particles may be solid matter or liquid droplets. PM10 particles (10 micrometres in diameter and smaller) are small enough to penetrate deeply into the lungs. Particles can aggravate existing respiratory and cardiovascular disease.

The current NEPM (National Environment Protection Measure) one-day standard for PM10 is 50 g/m3 (micrograms per cubic metre), with a maximum allowable exceedence of five days a year.

Particles result from various kinds of combustion, including bushfires and volcanoes. They are also emitted from industrial processes, motor vehicles, domestic fuel burning and industrial and domestic incineration.

Overall, air quality in Australia is relatively good. Between 1997 and 2001, the levels of PM10 in Brisbane, Sydney, Melbourne and Perth met the NEPM annual standard. However, there was a rise in 2002 and 2003, mainly due to severe forest fires and dust storms around the Sydney, Canberra and Melbourne areas.

Particulate concentrations, daily 24-hour PM10, selected cities
Graph: Particulate concentrations, daily 24-hour PM10, selected cities
Note: Shows the number of days when the one-day average concentrations exceeded the NEPM standard.
Source: State environmental protection agencies, 2007 and Environmental Protection and Heritage Council, < http://www.ephc.gov.au> last viewed June. 2007.

While four of the five cities with data available exceeded the one-day NEPM standard of 50 g/m3, the extent to which the standard was exceeded varied between cities. In 2005, Brisbane’s highest daily concentration was 52.6 g/m3, which exceeded the standard by 5%. Canberra’s highest daily concentration was 98.8 g/m3. This can be attributed at least in part, to emissions from domestic wood heaters.

Highest daily PM10 concentration, 2005
Graph: Highest daily PM10 concentration, 2005
Note: Shows the highest daily average concentration in micrograms per cubic metre.
Source: State environmental protection agencies, 2007.

Particulate concentrations, PM2.5

The National Environment Protection Measure (NEPM) was varied in 2003 to introduce advisory reporting standards for particles at PM2.5 (particulate matter with an equivalent aerodynamic diameter of up to 2.5 micrometres (m)).

The NEPM standard for particles up to PM2.5 is 25 g/m3 (micrograms per cubic metre) for one day.

Particulate concentrations, daily 24-hour PM2.5, selected cities

Graph: Particulate concentrations, daily 24-hour PM2.5, selected cities
Note: Number of days when the one-day average concentrations exceeded the NEPM standard of 25 g/m3.
Source: State environmental protection agencies, 2007 and the Environmental Protection and Heritage Council, <http://www.ephc.gov.au> last viewed June, 2007.

Particle pollution is a major air quality issue in Australia. Particles can aggravate existing respiratory and cardiovascular disease. Some plants and animals are particularly sensitive to fine particle pollution. Lichens for example are often among the first life forms to be affected, while particles can cover the leaves of larger plants and damage their ability to photosynthesise.

Highest daily concentration, 2005
Graph: Highest daily concentration, 2005
Note: Shows the highest daily average concentration in micrograms per cubic metre.
Source: State environmental protection agencies, 2007.
Levels of PM2.5 exceeded the NEPM standards in Sydney, Canberra, Melbourne and Perth in 2005.

Ozone (photochemical smog)

Ozone or photochemical smog is a problem in most large cities. It is caused by emissions from industry, motor vehicles, domestic wood combustion and other sources, accumulating under certain meteorological conditions.

Ozone is produced photochemically in air by reactions between hydrocarbons and nitrogen oxides. Some hours of strong sunlight are required to allow high levels of oxidant to form. High levels are most likely to occur when there is abundant sunshine combined with high temperatures and wind conditions that limit dispersion.

Ozone affects the linings of the throat and lungs, restricting air passages and making breathing difficult. It also increases the risk of respiratory infections and eye irritation. The current four-hour standard level of oxidant is 0.08 parts per million (ppm). The maximum allowable exceedance is one day a year.

Ozone has been monitored in most cities since the late 1970s. Ozone levels have declined significantly since the 1970s, although in recent years a clear trend is not apparent. There is significant year-to-year variability in peak ozone levels due to weather variability.

Daily peak 4-hour ozone (photochemical smog)
Graph : Daily peak 4-hour ozone (photochemical smog)
Note: Shows the number of days when the one-day average concentrations exceeded the NEPM standard.
Source: State environmental protection agencies, 2007 and Environmental Protection and Heritage Council, < http://www.ephc.gov.au> last viewed June. 2007.

The levels of ozone in the atmosphere vary between cities. Sydney was the only city that recorded a 4-hour ozone exceedence in 2005, as shown in the graph below. This is partly due to the topography of the Sydney Basin.

Highest daily concentration, 2005
Graph: Highest daily concentration, 2005
Note: Shows the highest daily average concentration in parts per million (ppm).
Source: State environmental protection agencies, 2007.

Sulphur dioxide

Sulphur dioxide (SO2) is a colourless, irritating and reactive gas with a strong odour. In Australia, emissions of sulphur dioxide are primarily from industrial operations that burn fuels such as coal, oil, petroleum and gas and from wood pulping and paper manufacturing. It is also emitted by vehicles. It irritates the eyes, nose and throat, and people with impaired lungs or hearts and asthmatics are particularly at risk of exacerbating existing health problems.

Ambient SO2 concentrations are generally low. Levels of SO2 vary between regions due to varied geographical distribution of major sources and different topographical and meteorological conditions. Sulphur dioxide levels in Australian cities are low compared to the USA and Europe because of the limited number of major SO2 emitting industries and low sulphur fuels.

Sulphur dioxide pollution has been an issue in some mining areas, but is generally improving. Due to improvements in mineral extraction and processing activities at Kalgoorlie in Western Australia, SO2 levels have been reduced dramatically over the last 12 years.

In recent years, one-hour SO2 levels have been below the National Environment Protection Measure (NEPM) standard levels at Gladstone, the Lower Hunter and La Trobe Valley (power generation areas using coal), however, levels remained high at Port Pirie and Mount Isa.

Sulphur dioxide, days of exceedence, selected regional centres
Graph: Sulphur dioxide, days of exceedence, selected regional centres
Note: The National Environment Protection Measure guideline for SO2 concentrations of 0.2 parts per million is the maximum allowable exceedences should be one day a year for one hour standard limit of sulphur dioxide.
Source: State environmental protection agencies, 2007 and the Environmental Protection and Heritage Council, <http://www.ephc.gov.au> last viewed June. 2007.

Carbon monoxide concentrations

Carbon monoxide (CO) is an odourless and tasteless gas, and cannot be detected by humans. Volcanoes and bushfires are natural sources of CO. In Australia, the main sources of additional CO are motor vehicles and specific industrial activities.

CO is poisonous to humans because it reduces the amount of oxygen that can be carried by red blood cells, resulting in insufficient oxygen reaching organs of the body to allow proper functioning.

The NEPM standard for CO is 9 parts per million (ppm) averaged over an 8-hour period. Between 2000 and 2005, no exceedances of the NEPM were recorded in Sydney, Melbourne, Brisbane, Perth or Adelaide.

Carbon monoxide concentrations, highest 8-hour concentration

Graph: Carbon monoxide concentrations, highest 8-hour concentration
Source: State environmental protection agencies, 2007.

Changes in the volume of road traffic impact on the concentration of atmospheric pollutants, such as carbon monoxide (CO).

There have been positive changes in fuel standards and vehicle design, resulting in a reduction in the concentration of CO in major Australian cities. This is despite a continued increase in the number of vehicles and the number of vehicle kilometres travelled.

In 2005, there were an estimated 13.9 million vehicles registered in Australia. Cars accounted for approximately three-quarters of all vehicles. Australian’s drove an estimate 206 billion kilometres in 2005, an increase of 8.5% since 2001.

MOTOR VEHICLE USAGE, million vehicle kilometres, Australia
Vehicle type
2001
2002
2003
2004
2005

Passenger vehicles
143 925
144 676
151 743
147 728
155 068
Motor cycles
1 448
1 681
1 376
1 478
1 429
Light commercial
30 728
31 349
32 671
34 007
33 764
Rigid trucks
6 627
7 080
7 768
7 639
7 671
Articulated trucks
5 321
5 425
5 841
6 013
6 308
Non-freight carrying trucks
267
224
203
221
286
Buses
1 835
1 775
1 893
1 968
1 856
Total
190 152
192 209
201 497
199 055
206 383

Source: ABS, Survey of Motor Vehicle Use (cat. no. 9208.0).



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