Ranked: Australia’s most polluted cities in 2025

Which Australian city has the dubious honor of the “most polluted” air? You might be surprised.

Despite Australia’s reputation for blue skies, certain urban pockets struggle with haze.

From big metros cloaked in traffic smog to regional towns downwind of bushfires, 2024’s air quality data reveals a few surprises in the nation’s pollution leaderboard.

In this deep dive, we rank every Australian city’s air — and explain what’s behind the haze.

Defining “City”: From Metropolises to Regional Hubs

First, what counts as a “city” in this ranking?

We aren’t using local council boundaries or metro areas; instead, we use the Australian Bureau of Statistics’ Significant Urban Area (SUA) definition.

SUAs group together continuous urban regions of at least 10,000 people, often spanning multiple suburbs or even states. For our purposes, we set a higher cutoff of 30,000 residents to focus on substantial cities. This captures obvious giants like Sydney and Melbourne, but also regional centers—think Ballarat, Bundaberg, or Coffs Harbour—that surpass the 30k mark. It also includes cross-border conurbations such as Albury–Wodonga (straddling New South Wales and Victoria) and Gold Coast–Tweed Heads (spanning Queensland/NSW).

In total, 50 Australian cities meet the ≥30k criterion, and all are ranked below.

Why PM_2.5 Is the Pollution Metric That Matters

Not all air pollution is created equal. We zeroed in on fine particulate matter (PM_2.5) as the key indicator of pollution for these rankings.

PM_2.5 refers to microscopic particles ≤2.5 microns in diameter – about 1/30th the width of a human hair. These tiny specks are especially dangerous because they can be inhaled deep into the lungs and even enter the bloodstream.

Health researchers link PM_2.5 exposure to lung and heart disease, strokes, and premature death. Australia’s national air standards reflect this concern: out of all pollutants measured (ozone, nitrogen dioxide, etc.), it’s PM_2.5 (and occasionally ozone) that most often exceed the official limits. In other words, even in Australia’s generally clean air, PM_2.5 is the pollutant to watch. It’s often the smoke you see (from bushfires or wood heaters) and the invisible soot you don’t (from vehicles and industry).

For each city, we looked at the annual average PM_2.5 concentration in 2024 (measured in micrograms per cubic meter, µg/m³) as the basis for our “most polluted” ranking.

Data Sources: State Monitors, IQAir and OpenAQ

Where does this data come from?

Australia has an extensive network of air quality monitors operated by state Environmental Protection Authorities (EPAs) and research organizations. Those official stations are the backbone of our data. In addition, global compilations like the IQAir 2024 World Air Quality Report aggregate readings from government monitors and validated citizen sensors.

In fact, over 60% of Australia’s PM_2.5 monitoring sites are run by non-government sources (universities, community networks, etc.), complementing the government stations. We tapped into OpenAQ’s open data platform as well, which collects readings from both EPA stations and reliable low-cost sensors, to fill gaps for some smaller cities.

For each city listed in the table, we’ve provided a “Data Source” link to the origin of its 2024 PM_2.5 figures. Most link to state EPA reports or IQAir’s city pages (which draw on official data). Where a city lacked a permanent monitor, we used the best available proxy data (for example, a nearby station or satellite-modelled estimate) and marked those cases.

Transparency is key: every number is rooted in a real dataset, and you can click the source to dig deeper. 

Australia’s Most Polluted Cities in 2024 (Annual PM_2.5)

Below is the complete ranking of Australia’s Significant Urban Areas (≥30k people) by their average PM_2.5 levels in 2024. For context, the national annual standard is 8 µg/m³, which is even stricter than the World Health Organization guideline of 5 µg/m³​.

Higher numbers mean dirtier air. We’ve noted the main pollution drivers for each city – from industries and traffic to woodfire heating or dust storms. If a city’s data was modelled or interpolated (due to no direct monitor), that is indicated in the notes.

Now, let’s see how your city fared:

*Notes: Cities marked with * had no dedicated year-round PM_2.5 monitor; values are best estimates from nearby data or short-term studies. All other cities’ averages are based on direct measurements by official monitoring stations or validated sensors. Annual values are rounded to one decimal place.

Discussion: Surprises and Takeaways

The ranking above holds a few surprises. Australia’s largest city, Sydney, does feature as one of the more polluted (with about 8.8 µg/m³). This is hardly shocking given Sydney’s traffic and frequent smoke intrusions.

But it’s notable that Sydney isn’t an extreme outlier – a handful of smaller cities are in the same ballpark. Industrial cities like Gladstone and Wollongong creep up the list due to their heavy industry, sometimes rivaling much larger metros for pollution.

Several inland towns – Tamworth, Dubbo, Wagga – rank relatively high too, largely because of winter woodfire smoke and occasional dust. Cold nights and wood-burning heaters can make air in a small country town as particle-laden as a busy city freeway. Mildura, on the semi-arid plains, shows how dust storms can elevate PM_2.5 even without big industry around.

On the other end, many regional cities and coastal areas enjoy very clean air. Canberra, the nation’s capital, for instance, averaged roughly 3.5 µg/m³ – impressively low thanks to minimal industry and favourable geography (barring the occasional bushfire smoke episode).

Coastal lifestyle cities like the Gold Coast, Sunshine Coast, and Albany benefited from ocean breezes dispersing pollutants. And Tasmania’s towns (Hobart, Devonport) remained among the cleanest, reflecting the island’s pristine environment and efforts to curb woodheater emissions.

Over half of the cities on this list met the WHO’s strict 5 µg/m³ guideline in 2024 – an impressive statistic few countries can claim. Even the worst Australian city averages are only on the order of 1–2 times the national standard, whereas many of the world’s megacities exceed those standards by 5–10 times.

It’s also worth noting that 2024 was a relatively mild year for bushfires (especially compared to the catastrophic 2019–20 season). In a bad fire year, the rankings can shift dramatically. For example, during the Black Summer fires, some normally clean country towns (like Armidale and even Canberra) temporarily recorded Australia’s highest PM_2.5 levels. The 2024 data above captures a more “typical” year – a snapshot of each city’s usual pollution sources without extraordinary events. Still, climate variability means no city’s clean air is guaranteed each year.

Clean Air Futures

The good news is that Australia remains one of the cleanest-air countries on Earth. All of our cities, even the “most polluted,” have annual PM_2.5 levels far below those seen in Asia or even parts of North America. This is a testament to strong regulations, effective monitoring, and a bit of geographic luck. But it’s not a reason for complacency. The urban pollution that does exist – whether from tailpipes, smokestacks, or woodfires – still affects millions of Australians. The fact that a place as small as Tamworth can breach national standards due to woodsmoke shows that pollution isn’t just a big-city problem.

The takeaway? Australia’s air quality is generally excellent, but it can be even better. Local and state initiatives are already targeting woodheater emissions, cleaner vehicle fuels, and better industrial controls. Community awareness is growing too – more people are checking air quality apps on smoky days and advocating for change. If there’s one silver lining in tracking the “most polluted” cities, it’s that we can identify trouble spots and tackle them. Whether it’s supporting cleaner industry in Gladstone or expanding green public transport in Sydney, the data empowers us to demand action. Year by year, as these rankings are updated, we hope to see those PM_2.5 numbers fall further.

In the meantime, Australians can breathe a little easier knowing that, overall, our air is clean – and together we can keep it that way, ensuring every city enjoys skies as clear as its neighbors.