Days over the air pollution limit are in a few towns, not the capitals
We counted the days each of 123 air monitoring stations in NSW, Victoria, Queensland, South Australia and the ACT went over the national limits in 2025. Eight stations, in Stockton, the Upper Hunter, Whyalla, Port Pirie, Wagga Wagga, Brooklyn and Moranbah, account for 44% of the days over the dust limit. No station went over the yearly fine-particle limit.
State environment agencies run air monitoring stations and publish what they measure. We took the 2025 readings from 123 stations in New South Wales, Victoria, Queensland, South Australia and the ACT and counted the days each one went over the national limits: 50 µg/m³ of PM10 (coarser dust) or 25 µg/m³ of PM2.5 (fine particles, mostly smoke) averaged over a day, and the one-hour limits for nitrogen dioxide and ozone.
Every station that measures fine particles was under the national yearly limit of 8 µg/m³. The highest was Melbourne's CBD at 7.9, and 30 of 98 stations were at or under the stricter World Health Organization guideline of 5. Days over the daily dust and smoke limits were few in the capitals and clustered in a few towns.
| Days over the limit, 2025 | Stations | With no days | Most at one station | |
|---|---|---|---|---|
| PM10 (dust) | 317 | 113 | 34 | 27, Stockton |
| PM2.5 (fine particles) | 110 | 98 | 43 | 9, Monash (Canberra) |
| Ozone | 11 | 59 | 51 | 3, Macquarie Park |
| Nitrogen dioxide | 0 | 70 | 70 | 0 |
A day counts once per station. Not every station measures every pollutant.
Dust: eight stations, 44% of the days
| Station | Days over the PM10 limit |
|---|---|
| Stockton, Newcastle | 27 |
| Warkworth, Upper Hunter | 23 |
| Whyalla, Walls Street | 22 |
| Port Pirie, Oliver Street | 17 |
| Wagga Wagga North | 14 |
| Mount Thorley, Upper Hunter | 14 |
| Brooklyn, Melbourne | 12 |
| Moranbah West | 10 |
These eight stations had 139 of the 317 days. Seven of them are near a port, a mine or heavy industry, Moranbah among them as a coal mining town; Wagga Wagga is the exception. The state agencies' own reports say:
- Stockton sits on the Port of Newcastle, about 300 m from the ocean. NSW's own studies found sea salt is the largest part of its PM10, highest when onshore winds blow in the warmer months.
- Warkworth and Mount Thorley are next to open-cut coal mines in the Upper Hunter. NSW reports that their readings are likely affected by the mines.
- Whyalla is a steelworks town. South Australia's EPA names PM10 from the steelworks, dry weather and dust storms as the main concern.
- Port Pirie is a smelter town. Its Oliver Street station is one of the two the EPA uses to track lead where people live.
- Brooklyn, 10 km west of Melbourne's CBD, is next to an industrial precinct. Victoria's EPA attributes about 30% of its dust on high days to trucks on the precinct's unsealed roads.
The capitals: a few days at most
Outside Brooklyn, no station in a capital went over the dust limit on more than five days. Sydney's stations had two at most. Brisbane's highest was Raceview, in Ipswich, with four. Adelaide's highest was Elizabeth with five, Canberra's was Civic with three, and Melbourne's next after Brooklyn was Dandenong with three.
Ozone went over the one-hour limit on 11 days across eight stations, all in New South Wales, and on three of them at Macquarie Park. No station went over the nitrogen dioxide limit.
Fine particles: winter smoke
Monash, in Canberra's Tuggeranong Valley, had the most days over the daily fine-particle limit: nine. The ACT's state of the environment report found wood heater smoke caused nearly 80% of the station's exceedances, with cold winter air holding the smoke in the valley. Wagga Wagga North and Armidale were next, with seven each.
How we measured
- Readings are each station's 2025 calendar year as published by the NSW, Victorian, Queensland and South Australian governments and ACT Health. Western Australia, Tasmania and the Northern Territory do not publish station data we can use, so they are not included.
- Where we count days from hourly readings, a day is over the limit if its average (PM10, PM2.5) or its highest hour (ozone, nitrogen dioxide) is over the national standard. New South Wales publishes its own counts, which we use as they are. For ozone, the standard uses four-hour averages; we count against the one-hour limit.
- ACT Health publishes its data before it is verified.
- A station measures the air where it stands. Each suburb page shows the nearest station in the same state, if one is within 30 km, so a suburb's figures can come from a station several kilometres away.
- Industrial sites that report their emissions are covered in one address in ten is within 1 km of one.