Worst air pollution Sydney, today and tomorrow
Today (17 September): Air quality in Sydney is moderate. AQI, PM2.5, and NO2 are moderate; PM10 and PM1 are fair; O3, SO2, CO, and HCHO are good. Pollution peaks around 10:00 PM (NO2: 45.9/100).
Tomorrow (18 September 2026): Air quality in Sydney is poor. AQI worsens to poor; NO2 increases to poor; all other pollutants stay as today. Pollution peaks around 8:00 PM (NO2: 72.4/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Australia's largest city has air quality shaped strongly by geography: the harbour and eastern suburbs benefit from onshore sea breezes, while western Sydney, ringed by hills that trap heat and pollutants, regularly records the city's worst summer ozone and highest bushfire smoke exposure, notably during the 2019–20 Black Summer. Spring brings a significant grass and tree pollen season across the basin, occasionally triggering thunderstorm asthma events, while winter can see wood-heater smoke and temperature inversions settle over some western suburbs. The harbour and coastal fringes generally record better air quality than the city's more enclosed western and southwestern basin areas.
Today - 17 September | Pollution peaks at 22:00
AQI:
Moderate
45.9/100
PM2.5 (fine particles):
Moderate
41.2/100
PM10 (coarse particles):
Fair
26.5/100
NO2 (nitrogen dioxide):
Moderate
45.9/100
O3 (ozone):
Good
11.0/100
SO2 (sulfur dioxide):
Good
5.9/100
CO (carbon monoxide):
Good
0.5/100
HCHO (formaldehyde):
Good
5.4/100
PM1 (ultrafine particles):
Fair
22.6/100
Levels show the poorest local air quality during the day
Tomorrow - 18 September | Pollution peaks at 20:00
AQI:
Poor
72.4/100
PM2.5 (fine particles):
Moderate
45.6/100
PM10 (coarse particles):
Fair
31.9/100
NO2 (nitrogen dioxide):
Poor
72.4/100
O3 (ozone):
Good
18.7/100
SO2 (sulfur dioxide):
Good
12.1/100
CO (carbon monoxide):
Good
0.8/100
HCHO (formaldehyde):
Good
10.9/100
PM1 (ultrafine particles):
Fair
38.0/100
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Frequently Asked Questions
Is air quality bad in Sydney right now?
On 17 September 2026, overall air quality in Sydney is moderate. AQI is the main air quality indicator at 45.9/100. Pollution peaks around 10:00 PM (NO2: 45.9/100).
Will air quality be worse tomorrow in Sydney?
On 18 September 2026, air quality conditions in Sydney will be worse than today, with AQI forecast at poor at 72.4/100. Pollution peaks around 8:00 PM (NO2: 72.4/100).
When is air pollution at its worst in Sydney?
Air quality is typically worst in western Sydney on hot, still summer days when photochemical smog builds against the surrounding ranges, and during bushfire season (spring through summer) when smoke can blanket the whole basin; the harbourside east generally fares better thanks to reliable sea breezes.
Are air quality levels in Sydney based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
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Data provided by Airmine — Last update: 16 September 2026 at 20:30 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
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