澳大利亚的空气质量

How bad is the air pollution in Australia?

Australia air quality is generally among some of the cleanest in the world, although the country is vulnerable to short-term extreme pollution spikes which occur due to bushfires and dust storms. However, since air pollution can have serious health impacts even at relatively low levels, it is important to strive to minimise exposure to Australia air pollution as much as possible. The health impacts of Australia air pollution can include decreased lung function, increased respiratory symptoms and risk of cardiovascular disease, lung cancer, shortened life expectancy and premature death.¹ Exposure to Australia air pollution is estimated to result in 4,880 premature deaths every year.²

Australia measures national air quality against its own air quality standards, called the National Environment Protection Measure for Ambient Air Quality (Air NEPM). The NEPM apply to 7 pollutants to which most Australians are exposed: carbon monoxide (CO), lead, nitrogen dioxide (NO₂), ozone (O₃), particulate matter (PM2.5 and PM10), and sulphur dioxide (SO₂).³ While the majority of these pollutants achieve Australia’s NEPM standards most of the time, particulate matter and ozone most frequently exceed the country’s standards for 24-hour exposure. Therefore, PM and ozone are Australia’s main pollutants of concern; although of these, PM2.5 is the most hazardous pollutant to Australian citizens’ health.⁴ PM2.5 describes microscopic airborne particles of 2.5 microns in diameter, which are particularly hazardous because their size enables them to penetrate deep into the human system upon inhalation, and enter the bloodstream, causing a range of health effects. It is for this reason that the Australian government is targeting particular efforts towards managing PM2.5 levels in future.¹

During 2019, Australia ranked as the 10th cleanest country of 98 included global countries in IQAir’s 2019 World Air Quality Report, with a countrywide average PM2.5 level of 8.0 μg/m³, weighted by population.⁵ This just achieves Australia’s NEPM standard for annual PM2.5 levels, of 8 μg/m³, and also achieves the World Health Organisation’s annual PM2.5 target of 10 μg/m³. This level ranked Australia as slightly more polluted for PM2.5 overall than Canada (7.7 μg/m³), neighbour New Zealand air quality (7.5 μg/m³), and Sweden (6.6 μg/m³), but cleaner than the United States of America (9.0 μg/m³), the United Kingdom air quality (10.5 μg/m³), and France (12.3 μg/m³).⁵

While Australia’s air quality averages out to a low level year-round, however, during extreme air pollution episodes such as bushfires and dust storms, some parts of Australia have temporarily experienced some of the worst air quality in the world. Real-time air quality information can be viewed at the top of this page within the dynamic Australia air quality map, which also includes live wildfire updates. These, along with a 7-day Australia air quality forecast can be followed at any time using the IQAir AirVisual air pollution app.

What causes air pollution Australia?

Australia air pollution comes from a range of both natural and human-made sources. Significant human-influenced air pollution sources include combustion in vehicle engines and from road traffic, industrial processes, power generation, and domestic wood heaters. Domestic wood heating is one major pressure on air quality during winter months in Australia, contributing at least 50% of winter ambient particulate matter.¹

Conversely, in urban areas, motor vehicles and road traffic are the main source of air pollution in general. Air pollution from road transport has been highlighted as one particular emission source where air quality improvements may be made in future, since the use of private transport is very high in Australia. Australia has one of the world’s highest rates of private vehicle ownership, with more than 90% of homes owning at least one registered motor vehicle. Furthermore, usage of public transport and active travel (such as cycling or walking) is low, in spite of 20% of work commutes in Australia’s major cities requiring travel under 5 kilometres. These trips could easily be replaced by walking or cycling, thereby lowering air pollution emissions.⁶

Two important natural sources of air pollution in Australia are dust storms and wildfires.

What causes dust storms in Australia?

Australia dust storms occur when strong winds lift dust and dirt from the ground, and carry it high in the atmosphere over a large area. The main sources of dust in Australia are dry lakes and deserts, with the Lake Eyre basin being the main source of Australian dust.⁷ Dust storms can cause health issues for some people, especially those from vulnerable groups (such as children, the elderly, those with pre-existing health conditions), and can cause negative impacts from severely limited visibility, such as increased traffic accidents. Dust can also sometimes carry bacteria and viruses with it, which can spread disease.⁷ Four main factors are needed for Australia dust storms to occur: strong enough winds to lift and carry the dust (higher than around 30 km/h); dry soil, so that it is loose and vulnerable to being picked up; an unstable atmosphere to enable the dust to be carried long distances, which is often present during thunderstorms or a strong cold front; and low moisture in the atmosphere, which increases the chances of the dust staying aloft and travelling further, rather than condensing and descending with rain.⁸

While Australia dust storms are relatively common, and are most likely to occur during spring when Australia experiences cold fronts, some episodes are more extreme than others. Sydney’s “Red Dawn” was a particularly dramatic dust storm impacting Sydney air quality and beyond, named after the thick red haze that greeted Sydney residents waking up on 23 September 2009. Caused by extreme winds in New South Wales triggered by a cold front and low pressure system, coupled with drought, the thick dust in this episode reduced visibility below 1 km for several hours, peaking with visibility limited to 400 m. It resulted in the closures of roads and disrupted flights and ferries, indicating the economic impacts dust storms can have.⁸ The only dust storm of comparable scale to Sydney’s “Red dawn” since 2009, occurred in mid-January 2020, following the devastating wildfires of Australia’s summer 2019-2020. Triggered partly by months of drought making the land surface loose and dry, together with strong winds from a low-pressure trough and storm system, this storm stretched for several thousand kilometres on 11 January 2020, even reaching New Zealand.⁷ With increasing global temperatures as part of climate change in future, warmer future conditions, limited rainfall and droughts could worsen these factors that enable dust storms to occur.

Are there still wildfires in Australia?

In addition to dust storms, wildfires are a common cause of extreme air pollution events in Australia. Australia has long had a fire season during the summer months when conditions are hotter and drier. Fires can either be started naturally, through a lightning strike, or through human intervention, through an accidental spark, or deliberately, through planned burning or arson.⁹ However, Australia experienced particularly devastating wildfires during the summer of 2019-2020, which came to be known colloquially as the “black summer”. The fires were particularly severe due to several months of record-breaking temperatures and droughts, which led to hotter and drier conditions than normal. As a consequence of the fires, which burned over 17 million hectares of land across the states of NSW, Victoria, Queensland, ACT, Western and South Australia, 33 people died, including 9 firefighters.¹⁰ Over 3,000 homes were destroyed, in addition to extensive numbers of animals, estimated at over 1 billion mammals, birds, and reptiles combined.¹⁰

The extensive fires also resulted in some world-leading levels of air pollution, causing more extensive human health impacts than direct fire-related casualties. A study published in the Medical Journal of Australia found that smoke generated during the bushfire crisis may have killed more than 400 people, while resulting in over 4,000 hospital attendances.¹¹ Wildfires can generate high levels of PM2.5, the most hazardous pollutant to human health, which can penetrate deep into the human system and cause a range of health effects. For people with pre-existing cardiorespiratory issues, exposure to Australia smoke can cause inflammation and make blood more likely to clot, increasing the risk of heart attack. Smoke exposure can also increase risk of asthma attacks, and the aggravation of existing conditions such as chronic bronchitis or emphysema.¹¹

How much pollution comes from coal in Australia?

While Australian levels of PM2.5 pollution are relatively low year-round by global comparison, this is not the same for all pollutants. In contrast to Australia holding one of the strictest standards in the world for PM2.5 pollution (annual mean concentration of 8 μg/m³, planned to be lowered to 7 μg/m³ by 2025), reports have found that Australia’s standards for sulphur dioxide (SO₂) pollution are among the most lax in the world, set at 11 times higher than the World Health Organisation’s recommended limit.¹² A Greenpeace report found that Australia’s SO₂ standards allow domestic power stations to emit higher levels of sulphur dioxide emissions than in China and the European Union.¹² The report furthermore identified some top-emitting single sources of SO₂ pollution within Australia, highlighting two power stations in Victoria’s Latrobe Valley, the Vales Point and Eraring coal-fired power stations in the Lake Macquarie region of New South Wales, and Liddell and Bayswater power stations nearby Muswellbrook within NSW’s Hunter Valley. Sulphur dioxide pollution can cause health problems such as heart and lung disease, and asthma. The health risks from SO₂ air pollution in Australia are therefore significant; nationwide, over 4,000 premature deaths are estimated to be caused by coal-fired power stations, while in Sydney alone, that number is 100 annual premature deaths.¹²

What is being done about air pollution in Australia?

Australia’s air quality management system is governed at both the national and local level. Since 1998, Australia’s air quality standards (Air NEPM) have been established to track air pollutant levels across the country, against science-based standards designed to limit health impacts. Australia’s state governments and Environment Protection Agencies (EPAs) work to try to ensure their states achieve these national standards.

In 2015, Australia furthermore established a National Clean Air Agreement (NCAA), agreed by all Australian environment ministers, which sets out a framework for prioritising air quality issues and effective policy. The framework combines several complementary strategies, including: monitoring against air quality standards; emission reduction measures; partnerships and co-operation; better knowledge, education and awareness; and priority setting.⁴ Some actions included in the initial work plan included reducing pollutant emissions from wood heaters, and non-road spark-ignition engines and equipment.⁴ To complement this nationwide program, two other national organisations have also established air quality initiatives. Firstly, the National Environment Science Programme has set up a fund of $8.8 million (AUD, equivalent to $6.5 million USD) over 6 years for a Clean Air and Urban Landscapes hub. While the fund is generally dedicated to research on how to build more liveable cities, some of these resources will be directed to address air quality priorities. Secondly, Australia’s Bureau of Meteorology is developing a National Air Quality Data Service, to consolidate all the national Australia air quality monitoring data gathered by the country’s separate state EPAs into one easily accessible database.⁴

What air quality index does Australia use?

Australia has also developed its own Australia Air Quality Index (AQI) system. The Australia AQI system is designed to communicate air pollution levels in an easy-to-understand way to the public, and quickly show the associated level of health hazard this represents. For each pollutant monitored at a given site, an AQI number is calculated as a percentage of the pollutant’s Air NEPM standard. Therefore, an AQI number of ‘100’ will represent that the pollutant has been measured equal to the national standard; an AQI of 200 shows the pollutant is double the recommended limit. Lower AQI numbers represent better air quality, from 0-33 representing “Very good”, up to 150+ representing “Very poor” air quality.¹ When multiple pollutants are being measured, the one with the highest AQI number will dictate that location’s overall Australia AQI.

Which city in Australia has the worst pollution?

During 2019, 13 out of the top 15 most polluted cities for annual PM2.5 concentration were based in New South Wales. This may be partly attributed to the fact that NSW air quality was the worst hit state by the impacts of the black summer’s wildfires.¹³ Australia’s most polluted city for PM2.5 pollution in 2019 was Armidale, exceeding Australia’s PM2.5 standard almost threefold (average concentration 23 μg/m³), followed by Tamworth (15.2 μg/m³) and the capital, Canberra air quality (15 μg/m³).⁴

Where is the best air quality in Australia?

Conversely, there is an equally strong trend indicating the cleanest state for Australia air quality: 23 out of 24 of Australia’s least polluted cities for PM2.5 pollution during 2019 were based in Tasmania.³ Within Tasmania air quality, the cleanest location emerged as the coastal town of St Helens, with an annual average PM2.5 concentration of 2.4 μg/m³; followed by Emu River (2.5 μg/m³) and Fingal (3 μg/m³).⁴

+ Article resources

[1] Dr Melita D Keywood, Dr Mark F Hibberd, Dr Kathryn M Emmerson. “Australia State of the Environment 2016: Atmosphere.” Australian Government Department of the Environment & Energy website, 2017.
[2] Clare Walter. “The public health impacts of air pollution in Australia: Research, policy and planning disconnects.” The University of Melbourne website, December 16, 2019.
[3] Australian Government. “National air quality standards: Ambient air quality (2016)”. Australia Government State of the Environment website, 2016.
[4] Australian Government. “National Clean Air Agreement”, Australian Government website, December, 2015.
[5] IQAir. “2019 World Air Quality Report”. IQAir website, March 18, 2020.
[6] Ting Xia et al. “Traffic-related air pollution and health co-benefits of alternative transport in Adelaide, South Australia”. Environment International 74, January, 2015: pp. 281-290. DOI: 10.1016/j.envint.2014.10.004
[7] Adam Voiland. “Major Dust Storm Sweeps Across Australia”. NASA Earth Observatory website, January 11, 2020.
[8] Australian Government Bureau of Meteorology. “Explainer: what is a dust storm?”. Bureau of Meteorology website, January 8, 2019.
[9] BBC. “How did Australia fires start and what is being done? A very simple guide”. BBC website, January 7, 2020.
[10] Parliament of Australia. “2019-20 Australian bushfires – frequently asked questions: a quick guide.” Parliament of Australia website, March 12, 2020.
[11] John Pickrell. “Smoke from Australia’s bushfires killed far more people than the fires did, study says”. The Guardian, March 20, 2020.
[12] Lisa Cox. “Australian power stations among world’s worst for toxic air pollution”. The Guardian, August 19, 2019.
[13] BBC. “Australia fires: A visual guide to the bushfire crisis”. BBC website, January 31, 2020.