Atmosphere Theme Report
Australia State of the Environment Report 2001 (Theme Report)
Lead Author: Dr Peter Manins, Environmental Consulting and Research Unit, CSIRO Atmospheric Research, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06746 9
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Human activity is inadvertently altering the make-up of the atmosphere. Burning of fossil fuels and deforestation are increasing concentrations of existing greenhouse gases, enhancing the natural greenhouse effect. There are also new greenhouse gases such as chlorofluorocarbons (CFCs) and CFC replacement gases being added to the atmosphere.
The enhanced greenhouse effect is likely to lead to warming at the earth's surface and to climatic changes.
CFCs and halons in the atmosphere are causing damage to the ozone layer. The damage is particularly severe over Antarctica in spring, producing the annual Antarctic ozone hole.
Ozone decline is not just a polar phenomenon - all regions apart from the tropics have shown a decline in stratospheric ozone from 1980 to 2000. As stratospheric ozone has declined, levels of ultraviolet (UV) radiation at the earth's surface have increased. Australians are now exposed to greater levels of UV radiation than previously.
Australians are concerned about pollution of our air. Atmospheric issues feature strongly in Australian's list of key environmental concerns, with air pollution remaining the environmental problem of greatest concern.
As with most environmental issues, pressures on the state of the atmosphere are closely linked to human population and activity. As an island continent, relatively isolated in the Southern Hemisphere, Australia suffers little from air pollution from beyond our borders. Our low population and technological sophistication limit air pollution problems, although our large cities and intensive industrial zones can put significant pressure on their local and regional environments.
Emissions of pollutants from motor vehicles and industry can cause pollution problems in cities. Rural areas downwind of cities and large industrial plants may also experience elevated pollution levels. Bushfires may generate fine particles, producing atmospheric haze.
The Framework Convention on Climate Change was strengthened by the Kyoto Protocol, agreed in principal in December 1997. The Protocol represents a significant advance in international efforts to combat global warming. For the first time, developed countries have considered legally binding commitments to reduce their greenhouse gas emissions and to address the threat of climate change. The United States stance in March 2001 has, however, caused a serious revision to general agreement.
As a whole, developed countries are committed to reducing their greenhouse gas emissions by at least 5% by 2008 to 2012 from 1990 levels. However, at Kyoto, Australia negotiated an 8% increase in emissions in the target period. By 1998, Australia's level of emissions had already increased by double this amount.
The National Greenhouse Strategy is a major policy initiative of the Commonwealth, state and territory governments. The Strategy provides the framework for Australia's greenhouse response, setting out a range of actions to be implemented by governments, industry and the community. The Commonwealth government in 1999 also committed significant funds to promoting the renewable energy industry and the use of alternative fuels, as well as implementing large-scale greenhouse gas abatement projects.
Discovery of stratospheric ozone damage led to establishment in 1987 of the Montreal Protocol, which has now been signed by over 165 countries. Since its inception, the Protocol has been regularly revised and tightened in response to scientific findings on atmospheric growth rates of ozone-depleting chemicals and on measurements of ozone destruction.
Production of the most damaging ozone-depleting substances was eliminated, except for a few critical uses, by 1996 in Australia and other developed countries and will be eliminated by 2010 in developing countries.
For the first time, Australia has an agreed set of national air quality standards to apply in all states and territories. In the National Environment Protection Council (NEPC) meeting on 26 June 1998, uniform standards were set for ambient air quality (ambient air does not include indoor air). These standards are contained in the National Environment Protection Measure for ambient air quality (the Air NEPM).
Emission data were both poor and sporadic before establishment in 1998 of the National Pollutant Inventory. This Inventory is an Internet database designed to provide the community, industry and government with information on the types and amounts of chemicals being emitted into the environment. It also shows the relative environmental effect of local industry and everyday activities. The National Pollutant Inventory represents a major advance in environmental management.
|Pollutant||Averaging period||Maximum concentration||Goal within 10 years A|
|Carbon monoxide||8 hours||9.0 ppm||1 day/year|
|Nitrogen dioxide||1 hour
|Photochemical oxidants (as ozone)||1 hour
|Sulfur dioxide||1 hour
|Lead||1 year||0.50 g/m3||None|
|Particles as PM10||1 day||50 g/m3||5 days/year|
A Maximum allowable exceedences.
Source: NEPC (1998).
Following introduction of Australian Design Rule 37/01 (ADR37/01) in 1997 to substantially reduce emissions from new petrol vehicles, in December 1999, the Commonwealth government announced its intention to harmonise Australian vehicle emission standards with more stringent existing and emerging European standards. The timetable for introducing new ADRs for petrol, diesel and alternative fuelled vehicles will see vehicle emission standards for new vehicles equivalent to Euro2 for diesels vehicles in 2002 to 2003, Euro3 for petrol vehicles in 2005 to 2006 and Euro4 for diesel vehicles in 2006 to 2007, and further European standards as they are developed. Reduction of sulfur levels in petrol to a maximum of 150 ppm will be required by 2005 as will a reduction in sulfur levels in diesel fuel to a maximum of 50 ppm by 2006.
Australian average surface temperature has increased by 0.76C over the past 90 years, which is consistent with the global temperature increase of 0.6 to 0.7C. The average minimum temperature has increased by 0.96C and the maximum has increased by 0.56C from 1910 to 2000 in Australia. The warmest years on record have been observed in the 1990s. The frequency of extreme warm days and nights has increased while the numbers of extreme cool days and nights have decreased. Frost frequency has also decreased.
Annual Australian mean minimum temperature anomalies.
Source: Bureau of Meteorology
Rainfall trends in Australia from 1910 to 1999.
Trends are shown as mm per 10 years, with positive numbers indicating increases.
Source: Bureau of Meteorology
Australian rainfall has increased slightly during the 1900s in most regions, except for south-west Western Australia and eastern Queensland, where decreases occurred. Australian rainfall shows strong interannual variability that is linked with variations in the El Nio-Southern Oscillation (ENSO) phenomenon.
Carbon dioxide concentration from ice core and air samples since 1000 AD.
The area of Australia experiencing extreme wet conditions has increased slightly, while the area of extreme dryness has reduced slightly since 1910. Heavy rainfall amounts and the number of heavy rainfall events have also increased in some areas.
The number of tropical cyclones in the Australian region has decreased since the late 1960s, a trend that can be linked to the decrease in the Southern Oscillation Index. However, the number of intense tropical cyclones has slightly increased during the same period. There is a strong interannual variability in the formation of tropical cyclones that is largely related to ENSO.
The last two decades (1980s and 1990s) were unusual in that there were more frequent occurrences of El Nio events compared with previous decades.
Production of Australia's major crops, such as wheat, rice and sugar shows strong interannual variability, which is associated with rainfall and ENSO.
Of all severe weather events, tropical cyclones cause the most extensive damage to human settlements, infrastructure and crops, with hailstorms second. However, the largest cost for a single event was the Sydney hailstorm of 1999.
The Australian government spent $700 million on drought relief payments or exceptional circumstance relief payments to farmers from 1992 to 1999. These droughts are associated with El Nio events, particularly the early 1990s and 1997 to 1998 events.
Mean sea level rise around Australia has been 12 to 16 cm during the 1900s. There is a strong link between sea level and ENSO. The estimated value of mean sea level rise around Australia is consistent with the global average given by the Intergovernmental Panel on Climate Change. Continued monitoring of sea level rise around Australia and correction of existing sea level measurements considering earth movements and other factors should lead to better future estimates.
Greenhouse gas concentrations show a large increase in the 1900s, upon which are superimposed strong seasonal variations. Measurement and monitoring of greenhouse gas concentrations in the atmosphere is of high quality, with Australia having an important role through observations taken at the Cape Grim Baseline Air Pollution Station and elsewhere. All measurements indicate faster increases of greenhouse gas concentrations than any observed over at least the past 1000 years.
A range of measures have been undertaken to reduce greenhouse gas emissions in Australia. Total greenhouse gas emissions increased by 16.9% between 1990 and 1998, from 389.8 to 455.9 Mt (excluding land clearing emissions).
Australia has very high carbon dioxide emissions in terms of per capita (with slowly increasing trend) and per unit of gross domestic product (GDP) (slightly decreasing trend). However, Australia's total carbon dioxide emissions are relatively small compared with other Organisation for Economic Cooperation and Development (OECD) countries, whose emissions are also predicted to rise.
The increase in per capita energy-related emissions since 1990 has driven the total increase in emissions per capita over this period. Any strategy that aims to reduce greenhouse gas emissions substantially should focus on the energy sector.
Improvement is needed in the data used to calculate the effect of carbon sinks and forest regrowth on the total greenhouse gas budget. Existing data show decreases in net emissions from land clearing between 1990 and 1998, although confidence in these figures is low. Work aimed at improving land clearing statistics will reduce uncertainties.
Rising greenhouse gas concentrations are likely to change Australia's (and the world's) future climate. These changes will have implications for many sectors of the Australian economy and society.
Atmospheric data show that the accumulation of total chlorine from ozone-depleting species in the stratosphere slowed during the early 1990s, stopped in the mid-1990s (maximum in 1994) and now is declining slowly. This is a significant development since the previous State of the Environment Report (SoE 1996), which described the early 1990s slowdown of total chlorine in the lower atmosphere.
Australian consumption of ozone depleting substances (ODS), based on production and import/export data.
Source: Environment Australia
Models indicate that stratospheric ozone responses lag the chlorine behaviour in the lower atmosphere by about three to five years, suggesting that stratospheric ozone depletion over Australia and Antarctica should have peaked in the late 1990s. However, there is no evidence to date of long-term ozone recovery over Antarctica.
Number of days during the year when the 24-hour average concentration of PM10 exceeded the Air NEPM level of 50 g/m3 in Australian cities.
Negative values indicate zero exceedences. Zero values indicate no data.
Source: State and Territory environmental authorities
Full recovery of stratospheric ozone to pre-1970s levels is unlikely to occur before 2050, and climate change could delay recovery until 2100.
Australian consumption of ozone-depleting substances remained well within its agreed Montreal Protocol limit throughout the 1990s. Consumption in 1999 (about 800 t) is close to the Protocol limit of 900 t for 1999 to 2000.
Skin-reddening UV levels over southern Australia and New Zealand on clear-sky days in summer have increased by up to 20% from 1980 to 2000. Other factors being equal, it is likely that this increase in UV has contributed to increasing incidences of UV-related diseases in Australia and New Zealand.
Number of days per year with maximum hourly ozone greater than the NEPM standard of 0.10 ppm for selected cities.
Negative values indicate zero exceedences. Zero values indicate no data.
Source: Commonwealth, State and Territory environment authorities
Of the criteria pollutants, there is little evidence in the capital cities of Australia of air pollution problems arising from sulfur dioxide, nitrogen dioxide or lead. Present trends indicate that carbon monoxide is unlikely to be of concern in the future. However, the recent finding of the Melbourne Mortality Study that both ozone and nitrogen dioxide are correlated with increased mortality, highlights the lack of knowledge of the synergistic effects of the pollutants, and indicates that monitoring of all of these pollutants needs to continue, as it will because of the reporting requirements of the Air NEPM. The strong epidemiological evidence that links exposure to particles and mortality has become widely appreciated since 1995; the Air NEPM includes a rigorous standard for particle smaller than 10 m in diameter, but mounting evidence points to the need for standards for still finer particles. Work on a NEPM for particles smaller than 2.5 m has commenced.
Despite a substantial decline in the number of occurrences through the 1980 to early 1990s in Sydney and Melbourne, there continue to be ozone episodes (i.e. when the Air NEPM standard is exceeded) in Sydney and Melbourne. However, as older motor vehicles are phased out and replaced by newer vehicles subject to more stringent emission controls, in particular Euro3 and Euro4 controls, these episodes should become less frequent. It is possible that as vehicle usage and numbers continue to rise, the sheer quantity of emissions may again lead to ozone episodes.
The passage of the National Fuel Quality Standards Act 2000 means that diesel fuel will be low in sulfur, and thus it will become realistic to expect heavy vehicles to install particulate traps and meet Euro3 limits on particulate emissions. Similar controls may also have to be introduced on cars. However, the benefits will take a long time to be evident because the measures only affect new vehicles and the fleet replacement time in Australia is about 11 years. More effective in the near term would be an inspection and maintenance program for existing vehicles.
Atmospheric particles resulting from seasonal woodsmoke are of concern in some cities. Current efforts to educate the community on appropriate use of domestic wood heaters are likely to take a long time to show substantial benefit.
There is insufficient regular, ongoing, monitoring of pollen counts despite over 40% of young adults suffering from hay fever and nasal allergies.
Increasingly, communities living near new and proposed freeways and road tunnels will demand air pollution measurements and, in the case of vent stacks, pollution reduction measures.
Knowledge of the air quality indoors (at home, in the workplace, in cars and in other transport vehicles) is poorer than knowledge of outdoor air quality. Australians spend from 90 to 96% of their time indoors, so further information is needed as to the pollutants to which they are exposed (see also the Human Settlements Theme Report).
Highest one-hour average concentrations of sulfur dioxide since 1985 in regional centres of Australia.
Source: Data from State EPAs, WA DEP
Although experiencing similar air quality issues to the capital cities, rural and regional Australia also have some distinctive air quality problems. Rural Australia's air pollution issues include windblown dust from mining and agricultural work, smoke, agricultural sprays and (likely) indoor air pollution. Regional Australia often owes its sustenance to nearby mining or mineral processing plants and can suffer consequences such as dust, sulfur dioxide, heavy metals, noise and odours.
The combination of low rainfall and strong winds can lead to high regional air pollution such as occurs with episodes of windblown dust. Add high temperatures and the result can be bushfires, which in turn can cause high levels of pollution. Australia is particularly susceptible to this combination of weather conditions.
One of the most important pollutants in a few locations is sulfur dioxide, which is closely identified with the processing of metalliferous ores. Total emissions of sulfur dioxide in Australia have decreased by almost one-third between 1995 and 2000. This is despite a substantial increase in mineral processed (e.g. Western Mining Company has increased ore processed in Australia by 36% to 24.5 Mt in 1999 over four years). A major reason for this improvement is the adoption of plant to convert sulfur dioxide to sulfuric acid instead of emitting it to the atmosphere.
The most important air quality issue in rural and regional Australia is management of airborne particles, whether they are haze, smoke, dust or particles smaller than 10 diameter (PM10) (which are respirable and therefore of concern for health). There are three distinct issues related to high PM10 m diameter (PM10) (which are respirable and therefore of concern for health). There are three distinct issues related to high PM10 that require attention:
- woodsmoke. The problems are the same as for the major cities, only more pronounced in some regional centres such as Launceston and Armidale and likely to be so in several other regions if only confirmatory monitoring data were available. More community education may be warranted.
- mining industry particle emissions. Industry's environmental awareness has increased greatly in the last decade and their willingness to undertake substantial measures to reduce dust emissions, including surveillance monitoring of the impact of their operations in their communities, seems to be working. Indeed, the embracing of the Australian Mineral Industry Code for environmental Management by members is a model that could well be followed by other groups.
- smoke from bushfires or fuel-reduction burns. Some of the major air pollution episodes recorded in capital city airsheds have occurred when smoke from regional controlled burning was trapped during periods of air recirculation.
Atmospheric lead concentrations at Port Pirie.
The Air NEPM Standard of 0.5 [mg]g/m3 (annual average) is shown for comparison.
Source: Pasminco (2000a)
Lead in air is no longer an issue in metropolitan Australia. However, substantial effort by industry is required before it can be said that all of Australia complies with the Air NEPM standard.
Fluoride emitted to the environment from industry warrants further study. Some ambient monitoring of fluoride is regularly done, but this needs to be made accessible to the public.
An issue that is difficult to assess, because only now is there growing indirect evidence for it, is that emissions from major urban regions are leading to high ozone in regional and rural Australia. New air pollution modelling shows the prevalence of such events in Victoria and eastern New South Wales. It is clear that without significant reductions in per capita emissions of ozone precursors, regional ozone pollution will worsen as urban centres continue to grow.
Air quality in rural and regional Australia is generally excellent, certainly by comparison with Australia's major cities, or cities in other countries. To keep it that way, and to improve conditions in those few places and occasions when air quality is not so good, continuous improvement will be needed. Self regulation, such as is being achieved by the minerals industry, is not always achievable, so there is an ongoing role for policy development in the areas of fuel reduction burning, use of wood heaters, agricultural practices such as pesticide spraying, land clearing and dust management from crop preparation and harvesting.