堪培拉的空气质量

How bad is the air quality in Canberra?

In general, Australian cities experience relatively healthy air quality year-round by global comparison. However, Australia’s annual seasonal bushfires during the warmer summer months have long punctuated the country’s usually clean air quality, with short-term smoke episodes. Australia’s capital city Canberra’s air quality fits this pattern. During the 2019-2020 summer season, Australia experienced particularly devastating wildfires, colloquially known as the country’s “black summer”. Canberra and the broader Australian Capital Territory (ACT) area in particular was subjected to extreme levels of prolonged air pollution from the black summer’s bushfires, temporarily registering as one of the most polluted cities in the world.¹

Real-time Canberra air pollution information is displayed at the top of this page, along with a 7-day air quality forecast and dynamic air quality map which also displays wildfire alerts. Stay on top of current conditions here and using the IQAir AirVisual air pollution app.

Where does air pollution come from in Canberra?

The main pollutants of health concern in Canberra are particulate matter: fine particles of up to 2.5 microns in diameter (abbreviated to PM2.5), or 10 microns in diameter (PM10). These tiny particles are present in smoke generated most commonly by wood heaters, bushfires, vehicle emission exhausts, and dust storms.² PM is particularly hazardous to human health since its tiny size enables the particles to penetrate deep into the human system once inhaled, even entering the bloodstream. Health impacts of exposure to particulate matter include an increased risk of cardiovascular disease, respiratory disease, and lung cancer. Since PM is a main pollutant found in the smoke emitted through bushfires, the health hazards of these pollution episodes for Canberra air quality are important.

During 2019, Canberra ranked as Australia’s 3rd most polluted city overall for hazardous PM2.5 pollution, with an annual average concentration of 15 μg/m³.³ This measurement exceeds both Australia’s strict annual air quality standard for PM2.5 of 8 μg/m³, as well as the World Health Organisation’s annual standard (10 μg/m³). Canberra air quality ranked below only the cities of Tamworth (23.0 μg/m³) and Armidale (15.2 μg/m³), both located in New South Wales. The capital also ranked with significantly higher annual PM2.5 levels than major cities Sydney air pollution (10.1 μg/m³) and Melbourne air quality (6.5 μg/m³). In global context, Canberra ranked as the world’s 49th most polluted capital city within a ranking of 84 global capitals by annual average PM2.5.³ This was more polluted than the capitals of Paris (14.7 μg/m³), Rome (12.9 μg/m³) and London (11.2 μg/m³).

Why is the smoke so bad in Canberra?

As one of Australia’s only planned cities, developed on land carved out of rural New South Wales as a diplomatic capital between major cities Melbourne and Sydney, Canberra is also known as the country’s “bush capital”.⁴ With plenty of bush “fuel” surrounding the capital, it is easy for bushfire smoke to reach the city during the annual fire season. However, two other key factors relating to Canberra’s geography can exacerbate smoke once it has reached the city: its location as a valley surrounded by mountains, and its wind patterns. Firstly, Canberra’s location between two mountain ranges, the Brindabellas to the west and the Great Dividing Range to the east, results in a “bowl”-like shape, which can trap fog during winter months, and smoke during the hotter fire season.⁵ This valley shape also helps to prolong a weather phenomenon known as a temperature inversion, which traps pollution for longer periods. Usually, air is warmer closer towards the ground, while air becomes cooler higher up; during a temperature inversion, certain conditions lead ground-level air to become cooler, while hotter air rises above and acts like a lid, trapping the cooler air below the inversion. During summer, Canberra’s winds are typically east or south-easterly, bringing in air that’s cooled from the sea. However, during wildfire season, these same winds can also bring particulates and soot from New South Wales wildfires to the east of Canberra which then get trapped under the temperature inversion lid.⁵ This was what occurred during Australia’s black summer of 2019-2020, and could facilitate similar conditions for Canberra air pollution again in future.

Is Canberra safe from the fires?

During the majority of the year, particularly winter months, Canberra experiences relatively healthy air quality. During 2019, the months of January to October ranged between monthly average PM2.5 levels of 6.8 μg/m³ to 11.1 μg/m³, with a mean of 8.9 μg/m³. While this slightly exceeds Australia’s national legal annual target of 8 μg/m³, this is within the World Health Organisation’s recommended annual limit of 10 μg/m³. Only during the last two months of 2019 did particulate pollution start increasing significantly, with 12.6 μg/m³ in November 2019, and a much higher 74.1 μg/m³ in December 2019.³

While the winter months therefore provide some relief from the bushfire-related air pollution, it is likely that Canberra may be subject to seasonal haze from wildfire smoke in the summer months again in future. However, due to the amount of bushfire “fuel” that was burned up during 2019-2020’s black summer, experts predict that Australian bushfires may not reach such destructive levels for the subsequent 3 to 5 years as the land recovers.⁶

What AQI does Australia use?

Australia uses an Air Quality Index to communicate air quality readings to the public. Canberra’s state, the Australian Capital Territory (ACT) uses the national Air Quality Index system to communicate a Canberra Air Quality Index, which is based on the 5 pollutants monitored within the state. These are PM2.5, PM10, ozone, nitrogen dioxide, and carbon monoxide. ACT does not monitor sulphur dioxide due to a lack of heavy industry.² The Canberra AQI is calculated as a percentage of the national limit outlined by the National Environment Protection Measure Ambient Air (NEPM) standards for each pollutant, whereby an AQI of 100 represents the maximum allowable amount (100%) of a given pollutant, and AQI numbers above 100 represent an excess of the national limit.⁷ According to this Canberra AQI scale, AQI levels of 0-33 are ‘Very Good’, while readings of 200+ register as ‘Hazardous’.

Does Canberra have the worst air quality in the world?

During Australia’s black summer of extreme bushfires between 2019-2020, Canberra did briefly register as one of the most polluted cities in the world. On New Year’s Day (1st January) 2020, following some days of heavy air pollution, Canberra air quality reached an extreme peak. At 1am on New Year’s Day, one of Canberra’s 3 monitoring stations registered an AQI reading of 7,700 – representing a staggering excess of the Australia air quality limit by 77 times, well into the ‘Hazardous’ AQI level of above 200.¹

+ Article resources

[1] Amy Remeikis. “Canberra chokes on world’s worst air quality as city all but shut down”. The Guardian, January 3, 2020.
[2] ACT Government. “Air pollutants and sources”. ACT Government website, September 3, 2019.
[3] IQAir. “2019 World Air Quality Report”. IQAir website, March 18, 2020.
[4] ACT Government & Canberra Museum + Gallery. “Bush Capital: the natural history of the ACT”. Bush Capital website, 12 March – 26 June, 2016.
[5] Markus Mannheim. “NSW fires will continue to blanket Canberra in smoke for foreseeable future, experts say”. ABC News Australia, January 7, 2020.
[6] Kevin Tolhurst. “It’s 12 months since the last bushfire season began, but don’t expect the same this year.” The Conversation, June 10, 2020.
[7] ACT Government. “Measuring air quality: Air Quality Index”. ACT Government website, n.d.