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The major source of GHG emissions was the energy sector (including stationary energy, transport and fugitive emissions from fuels) which accounted for 391.0 mill. tonnes of CO2-e (69.9%) of total national emissions in 2005 (graph 3.24). The agriculture sector contributed a further 87.9 mill. tonnes of CO2-e (15.7%); land use, land use change and forestry sector contributed 33.7 mill. tonnes (6.0%); industrial processes 29.5 mill. tonnes (5.3%); and waste 17.0 mill. tonnes (3.0%).
Emissions from the waste sector declined by 7.1%, from 18.3 mill. tonnes of CO2-e in 1990 to 17.0 mill. tonnes in 2005. This decline was largely due to a decline in both waste water handling and solid waste disposal on land. The emissions from the land use, land use change and forestry sector declined from 128.9 mill. tonnes of CO2-e in 1990 to 33.7 mill. tonnes in 2005. This decline reflects the greenhouse sink offset resulting from afforestation and reforestation in the forestry subsector.
While Australia only accounts for around 1.5% of global GHG emissions, its CO2 emissions per person are relatively high compared with other OECD countries. In 2004, 17.5 tonnes of CO2 were emitted for every Australian compared with an OECD country average of 11.1 tonnes of CO2 per person (graph 3.26). Australia’s relatively large emissions per person can be attributed to factors such as the high usage of coal in electricity generation, the energy intensive aluminium smelting sector, and the high dependence on motor vehicles and trucks for transport.
In 2004, the emissions intensity of the Australian economy (0.8 kg CO2 per dollar of GDP) was relatively high compared with the OECD average (0.5 kg CO2 per dollar of GDP) (graph 3.27). However, Australia’s emissions intensity declined by 37% over the period 1990 to 2005 from 1.0 to 0.7 kg CO2-e per dollar of GDP. This trend reflects factors such as the large decline in emissions from agriculture and forestry, structural changes in the Australian economy with a shift away from energy intensive manufacturing to the services sector, and the impact of emissions management across the sectors.
Air pollutant levels are not considered to be high in urban Australia (relative to other world cities). However, poor air quality can have a number of negative impacts on both environmental and human health. For example, an increase in atmospheric nitrogen oxides contribute to acid rain, and exposure can lead to a fatal excessive fluid build up in the lung tissues (pulmonary oedema) in humans. Further, it has been estimated by the Bureau of Transport and Regional Economics, that in 2000, motor vehicle air pollution accounted for between 900 and 2,000 early deaths with an associated economic cost of between $1.1 and $2.6 billion.
Air pollutants are grouped into two broad categories; indicator (or criteria) air pollutants and air toxics, sometimes called hazardous air pollutants. Hazardous air pollutants include heavy metals, volatile and semi-volatile organic compounds, polycyclic aromatic hydrocarbons and aldehydes. The sources of hazardous air pollutants are primarily related to human activities, for example industry, motor vehicles and wood heaters. Motor vehicles are typically the largest source of hazardous air pollutants in urban areas and are the largest source of benzene; toluene; 1,3-butadiene; and lead. Wood heaters are also a source of hazardous air pollutants, especially in winter. Emissions from domestic fuel combustion include benzene, aldehydes and metals.
The effects of exposure to hazardous air pollutants vary but cases of cancer, birth defects and respiratory disorders have been linked to exposure to air toxics. The National Environment Protection Measure (NEPM) for Ambient Air Quality is the national objective for managing air pollutants.
Carbon monoxide (CO)
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. The pollutants emitted by road transport contribute to poor air quality that damages human and ecosystem health. Changes in the volume of road traffic impact on the concentration of atmospheric pollutants, such as CO. Despite a continued increase in the number of vehicle-kilometres travelled (table 3.28), rising by 8.5% from between 2001 and 2005, there have been positive changes in fuel standards and vehicle design, resulting in a reduction in the ambient air concentration of CO in high traffic areas of major Australian cities.
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 can affect the linings of the throat and lungs, restricting the air passages and makes breathing difficult. It also increases the risk of respiratory infections and produces eye irritation. It is one of the main air quality issues in Sydney, occurring mainly in summer.
The current one-hour standard level for ozone is 0.10 parts per million (ppm). The maximum allowable exceedence should be one day a year. Ozone has been monitored in most Australian cities since the late-1970s. Ozone levels have declined significantly over that period although in recent years the trends are not as apparent. There is significant year-to-year variability in peak ozone levels due to weather variability. Exceedence of the current ozone standards are occasionally observed in most major Australian cities, with more frequent exceedences observed in Sydney partly due to the topography of the Sydney Basin (graph 3.29).
SO2 is a colourless, irritating and reactive gas with a strong odour. In Australia, emissions of SO2 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 vary between regions due to varied geographical distribution of major sources and different topographical and meteorological conditions. SO2 pollution has been an issue in some mining areas, but is generally improving. Due to improvements in mineral extraction and processing activities at Kalgoorlie (Western Australia) , SO2 levels have been reduced over the last 12 years (graph 3.30). In the Illawarra district (New South Wales) the smelting operations at Port Kembla have recently ceased and SO2 levels are expected to reduce. In recent years, one-hour SO2 levels have been below the NEPM standard levels at Gladstone (Queensland), the Lower Hunter and La Trobe Valley (Victoria) (power generation areas using coal), however levels remain high at Port Pirie (South Australia) and Mount Isa (Queensland).
PM10 (particles of 10 micrometres in diameter, or approximately one-tenth of the width of a human hair) and smaller particles are small enough to penetrate deeply into the lungs. Particles can aggravate existing respiratory and cardiovascular diseases and may be solid matter or liquid droplets. Particles are emitted from industrial processes, motor vehicles, domestic fuel burning and industrial and domestic incineration and also result from various kinds of combustion, including bushfires and volcanoes.
The sources of particle pollution differ between areas. Climate and topographical conditions influence particle levels. In warmer regions, such as Sydney and south-east Queensland dry conditions can contribute to bushfires and windblown dust. Whereas in Launceston (Tasmania) and Canberra, the use of domestic wood fires for heating in winter can lead to high particle levels and in Melbourne particle levels can be raised by motor vehicle emissions (graph 3.31).
The current 24-hour standard for PM10 is 50 micrograms per cubic metre (µm/m3) with a maximum allowable exceedence of five days a year. Between 1997 and 2001, the level of exceedence for fine particle health standards in selected urban areas on average was acceptable. There was a rise in 2002 and 2003, mainly due to severe forest fires and dust storms around the Sydney, Canberra and Melbourne areas (graph 3.32).
The NEPM Ambient Air Quality was varied in 2003 to introduce particles at PM2.5 (particulate matter with a diameter of up to 2.5 micrometres (µm), in the form of advisory reporting standards. The current standard for PM2.5 is 25 µm/m3 in a 24-hour period (graph 3.33).
PM2.5 is a pollutant of concern, having peak concentrations at or above the NEPM standards at three jurisdictions in 2006 - New South Wales, Queensland and the Australian Capital Territory.
The NPI is a database designed to provide the community, industry and government with information on the levels of certain pollutants emitted to air, land and water from industry and other sources. It provides information on the quantities of pollutants emitted as well as their source and location. The NPI currently holds emission data for close to 4,000 facilities, 33 airsheds and 32 catchments around Australia. Currently, large industrial facilities estimate their own emissions annually (by completing a reporting form), with 'aggregated emissions' from households and other sources being estimated by government agencies.