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Fine particle concentrations in selected urban areas(a), days health standards exceeded(b)
Overall, air quality in Australia is relatively good and has generally improved during the 1990s.1 Our cities do not suffer from the acute pollution problems found in many OECD countries.2 Health standards were exceeded in the selected urban areas on average between one and two days each year between 1997 and 2001. There was a rise in 2002, mainly due to severe forest fires and dust storms around the Sydney area which caused the NEPM goal to be exceeded on 13 days in Liverpool that year. The goal was also exceeded on six days in Brisbane. Sydney and Brisbane recorded no and one day’s exceedences, respectively, in 2001.
Progress and the headline indicator
Human settlements have an impact on the landscape and seascape that surrounds them. They can also provide a home for native plants and animals. But the environmental quality of settlements is perhaps most important because it has an influence on those who live and work within them.
Several environmental concerns are associated with human settlements. It is difficult to conceive an ideal headline indicator which might measure progress against each and so we choose one. For about a decade, the Australian public has been more concerned about air pollution than about any other environmental problem.
Poor air quality has a range of negative impacts: it can cause health problems, damage infrastructure, reduce crop yields and harm flora and fauna. For about a decade, the Australian public has been more concerned about air pollution than about any other environmental problem.4 A recent report estimated fine particle pollution had been linked to the deaths of up to 2,400 people a year in Australia, with an associated cost of $17.2b.6
Ideally, a headline indicator would encapsulate all aspects of air quality. But pollution takes many forms and there is, as yet, no agreed way in which different pollutants could be combined into just one measure. The headline indicator considers the concentration of fine particles in the atmosphere (see box), a measure of the form of air pollution about which many health experts in Australia are most concerned.5
Most pollutants are more common in urban and industrial areas than in rural Australia. As there is little long-term information about air quality over much of Australia, the headline indicator graph summarises data from continuous air monitoring stations in Sydney, Melbourne, Adelaide, Perth and Brisbane.1 It is important to note that dailychanges in air quality depend on ambient conditions, like wind direction and the monitoring station's proximity to pollution sources. Further, high concentrations of fine particles from irregular events, such as forest fires, can obscure the longer trend in levels produced by regular sources, like car emissions.
Health standards were exceeded in the selected urban areas on average between one and two days each year between 1997 and 2001. There was a rise in 2002, mainly due to severe forest fires and dust storms around the Sydney area which caused the National Environment Protection Measure (NEPM) goal to be exceed on 13 days in Liverpool that year. The goal was also exceeded on six days in Brisbane. Sydney and Brisbane had recorded no and one day's exceedences, respectively, in 2001.
The station in Melbourne recorded air quality exceeding guidelines on four days in both 1997 and 1998, but on only two days or fewer per year between 1999 and 2002.
Air quality in Brisbane exceeded guidelines on two days in 2000, and on no or only one day in other years between 1997 and 2001. The Perth station recorded four days exceedences in 1997, but no more than a single day's exceedence in each year between 1998 and 2002. The station in Adelaide recorded air quality guidelines were exceeded on two days in both 1997 and 1998, and five days in 1999. Between 2000 and 2002, the levels of fine particles in the air met the NEPM standard every day.
Other pollutants also have negative impacts. In urban areas concentrations of lead levels dropped significantly during the 1990s and, together with sulfur dioxide and nitrogen dioxide, they are not a concern in any urban areas.2 Carbon monoxide is only of concern in a few specific urban localities, but there has been no real drop in the incidence of photochemical smog (see Ozone and photochemical smog section later).2
Some differences within Australia
Different parts of the country experience different types and levels of air pollution, but air quality outside the major cities seems generally good, and levels of pollutants are generally well below actual or proposed standards.2 Fine particles (particularly wind blown dust) are often the principal air pollution problem in most of our regional centres.2 In places like Armidale, Canberra and Launceston, fine particle pollution is closely associated with domestic wood fires used for winter heating.6 Some areas, far from major sources of pollution, can suffer from the long range transport of pollutants. Bushfires and controlled burn-offs also pollute.2
The headline indicator focused on one form of air pollution: fine particles. Other substances released into the air can be harmful to both people and the environment. Some substances pollute directly and are known as primary pollutants. Others (so-called secondary pollutants) react with the atmosphere, or each other, to produce pollution. This section begins by looking at sulfur dioxide (a primary pollutant) and then considers ozone and photochemical smog (formed from secondary pollution by oxides of nitrogen).
There appears to have been overall progress in the 1990s. Sulfur dioxide emissions dropped by 30% between 1996 and 2001, while dust loads in mining areas have been reduced.2 However, there remain some localised problems in areas such as Port Pirie and Mount Isa.2
Climate is an important determinant of the amount of pollution experienced in Australia's cities and when it occurs. Weather patterns that result in low or no wind are more likely to produce air pollution. Pollution conducive days usually occur in the summer and spring in all of our coastal capital cities. Brisbane can also expect them in the winter.4
Ozone and photochemical smog
Ozone is formed when oxides of nitrogen react with sunlight in the atmosphere. It is a colourless gas and a natural part of the upper atmosphere, where it filters ultraviolet radiation from the sun. But increased concentrations in the lower atmosphere can irritate eyes and kill vegetation.
In parallel with ozone formation, nitrogen dioxide reacts with substances in the atmosphere like water vapour to form acid aerosol nitrates. These mix with ozone to form smog. As sunlight is an important factor in the formation of ozone (and hence smog), smog is more likely on sunny days in cities.
Number of days when ozone concentrations exceed guidelines(a), selected capital cities(b)
Highest one hour averages of SO2, selected regional centres(a)
A recently published study linked ozone and nitrogen dioxide pollution with increases in daily death rates in Melbourne.8
Ozone concentrations, therefore, provide an estimate of smog. During the 1990s there was no real decline in the number of days when maximum hourly ozone concentrations (averaged over four hours) exceeded guidelines in our five largest capital cities, and hence no decline in smog.2 Between 1992 and 2002, four-hourly ozone guidelines were broken on 132 days in Sydney, 32 days in Melbourne, 22 days in Perth and nine days in Brisbane.
Sulfur dioxide emissions
Sulfur dioxide (SO2) is emitted by the burning of coal and during industrial processes such as 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 developing health problems.9
Most of Australia is now unaffected by sulfur dioxide pollution. And in 2002, prompted by a 30% reduction in SO2 emissions during the late 1990s, there were only a few localities of concern.2 There were no exceedences in recent years in the Illawarra and Gladstone areas, where coal-fired power generation occurs.2
Maximum concentrations have also fallen dramatically in Kalgoorlie in recent years (because of improved mineral extraction and processing)2 and were under the NEPM guideline in 2002. By comparison, Mt Isa's maximum concentrations also declined during the 1990s, but rose sharply in 2002 (when weather conditions forced the smelter plume to the ground near the monitoring station; stations nearby recorded much lower concentrations).
Factors influencing change
Our air has always contained natural substances like sea-salt or gases from decaying plants and animals. But industrial activity and the growth in fossil-fuel dependent traffic have released millions more tonnes of pollutants into the air (over a million tonnes of PM10 emissions alone in 2002-03)10. Most of these emissions (20%) are from the use of fossil fuels.
Motor vehicles are Australia's single largest source of air pollution.2 For example, in 2002-03, in the Sydney-Newcastle-Woollongong NSW Airshed, the largest single source (more than 25%) of all PM10 emissions was motor vehicles.10 Cars and trucks generate particles directly through burning fossil fuels, especially diesel. Diesel generates far more particles than petrol per litre, and generates more of the finest particles (smaller than 2.5 micrometres) which have serious health implications for humans.11 Vehicles also generate particles when tyres lose rubber, and tyre and air turbulence wear away road surfaces.
Motor vehicles also emit other types of air pollution. In the mid-1990s, traffic accounted for more than 75% of emissions of carbon monoxide (which can affect memory and vision, cause heart disease and harm unborn children), and most of the oxides of nitrogen (which contribute to smog), and was a major contributor to many volatile organic compounds (which contribute to smog).2 Industries that contribute to fine particle pollution include those that burn fossil fuels to make heat and power (such as power plants, and iron and steel works), refineries, mines and quarries, cement works, mineral processing plants and some agricultural activity (controlled burning and eroded soil generate fine particles).10 Domestic wood heating can also have a significant effect.2
But although industrial activity and the numbers of cars grew during the 1990s, measured air quality has not deteriorated significantly. Technology and strategies designed to control air pollution appear to have countered the rises which would have been expected given the increases in pollution sources.4
For instance, diesel vehicles contribute almost three-quarters of all vehicular fine particle emissions. However, projections prepared for the National Road Transport Commission suggest that by 2015, despite significant growth in numbers of diesel vehicles (light commercial vehicles in particular), fine particle emissions from all diesel vehicles will fall in the major cities to about 70% or less of their 1996 levels.12 The main reason for the predicted fall is that older vehicles will be replaced by newer, less polluting vehicles. Cars and trucks are becoming cleaner in other ways too. For example, the switch to unleaded petrol and the use of catalytic converters has led to significant reductions in lead pollution in some areas (lead concentration at Mascot, inner Sydney, fell by some 60% between 1993 and 1996).13 A greater use of renewable power sources to generate energy could also reduce some forms of air pollution.
Substantial quantities of waste are generated from human consumption and activities related to the construction, operation, maintenance, and renewal of human settlements.14 Solid, liquid and gaseous wastes are a by-product of many productive processes, and goods (or their packages) may be discarded by consumers.
Waste can be expensive to deal with and can have a damaging impact on the environment or even affect people's health. This commentary sheds some light on three important aspects:
The amount of waste generated tends to increase with the size of human settlements and the level of industrial activity. The volume and type of waste disposed of by Australian households and industries have varied over time, as has the rate at which resources are being recycled and reused. This commentary focuses on the disposal and reuse of solid wastes. Waste water is also important, and is discussed in the commentary Oceans and estuaries.
The costs imposed by waste generation go beyond the financial costs of processing, treatment and transportation to landfill sites. Waste-related pollution and contamination can affect the environment and human health. However, in some circumstances, waste can be recycled, reducing the volume of natural resources that must be extracted or harvested to support future production and consumption.
When assessing progress in this area, one might want to bear in mind three major aspects. The first involves minimising the amount of waste generated. The second is to use the waste that is generated as resources where possible. The final aspect involves disposing of whatever waste cannot be recycled in a manner that is least harmful to the environment, the health of the population and economic progress. An ideal indicator of progress might capture all three aspects.
Waste can originate from a number of sources: households and councils; building and demolition sites; and commercial and industrial sources.
Waste from households is generally made up of organic (food and 'green') wastes, paper, glass, metal and plastic. Councils are also responsible for collecting and disposing of litter (such as cigarette butts, bottles, cans, and packaging materials), often at a significant economic cost. Loose litter can also contribute to stormwater pollution which, in turn, can affect water quality on beaches and in waterways.15
Recycling, Australian Capital Territory
Industrial waste and recycling
The volume of commercial and industrial waste disposed of as landfill varies significantly by industry sector. For instance, a landfill audit in South Australia found that 45% of all commercial and industrial waste is generated by the manufacturing sector, with retail trade (17.5%) the next largest contributor.19
An increasing number of industries are using recycled materials as inputs into the manufacturing process. Examples include the recycling of steel and aluminium cans by manufacturers of packaging.
Another example is the use of bagasse (the residual waste from raw sugar processing). The heat produced by burning bagasse is used to power machines that crush sugar cane, and also for electricity generation. Other biomass resources (i.e. biological materials used as fuels) used to generate electricity include: black liquor at paper pulp plants, sawmill waste, and woodchips.20
Links to other dimensions of progress
Air quality is linked to health. While the full effects of pollutants like fine particles are still poorly understood, Australian studies are consistent with those overseas which show that days of high pollution levels show increased mortality rates, hospital admissions and emergency room visits for respiratory and cardiovascular disease.4
Polluted air can harm biodiversity: smog and acid rain can affect many plants and animals.21
Air quality is linked to the generation of income. Economic activity, especially among the more energy-intensive industries, creates pollution. But in turn, air pollution has financial impacts, such as the cost of cleaning buildings, while acidic gases in the atmosphere can corrode iron and steel. Agriculture can also be affected: polluted air can harm crops and livestock.
Land clearance and degradation contribute to air pollution: fine particles are created when vegetation is burnt, and when eroded soil is blown into the air.
High levels of waste can impose adverse effects on the environment, particularly if not contained and managed effectively. The quality of land surrounding waste disposal sites can also be affected. Land degradation may occur if adequate measures are not taken to prevent substances such as oils and tars, metals and organic compounds from contaminating landfill sites and the areas surrounding them. Waste is also related to greenhouse emissions (the decomposition of organic waste releases methane, a greenhouse gas, into the atmosphere).
See also the commentaries National income, Transport, Health and The natural landscape.