Worst air pollution Hornsby - Sydney, today and tomorrow
Today (25 August): Air quality in Hornsby is good. AQI, PM2.5, PM10, NO2, O3, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 11:00 AM (O3: 14.7/100).
Tomorrow (26 August 2026): Air quality in Hornsby is fair. AQI worsens to fair; NO2 increases to fair; all other pollutants stay as today. Pollution peaks around 11:00 PM (NO2: 30.9/100). Airmine updates local air quality forecasts four times daily.
Get the full experience in the Airmine app.
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
Follow your pollen exposure and performance with the free Airmine–Strava integration. See your pollen and air quality exposure for every Strava activity.
Hornsby sits on an elevated ridge on Sydney's Upper North Shore, surrounded by extensive bushland reserves, a setting that supports generally good air movement despite fairly busy traffic along the Pacific Highway and rail corridor through the town centre. This bushland proximity makes Hornsby more exposed to bushfire smoke in dry summers than harbourside suburbs closer to the water. There is no industry here. Overall, background air quality is good, balancing traffic through the centre against extensive surrounding green space.
Today - 25 August | Pollution peaks at 11:00
AQI:
Good
14.7/100
PM2.5 (fine particles):
Good
5.6/100
PM10 (coarse particles):
Good
1.6/100
NO2 (nitrogen dioxide):
Good
12.5/100
O3 (ozone):
Good
14.7/100
SO2 (sulfur dioxide):
Good
5.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
6.4/100
PM1 (ultrafine particles):
Good
7.6/100
Levels show the poorest local air quality during the day
Tomorrow - 26 August | Pollution peaks at 23:00
AQI:
Fair
30.9/100
PM2.5 (fine particles):
Good
8.5/100
PM10 (coarse particles):
Good
2.8/100
NO2 (nitrogen dioxide):
Fair
30.9/100
O3 (ozone):
Good
18.3/100
SO2 (sulfur dioxide):
Good
7.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.8/100
PM1 (ultrafine particles):
Good
8.4/100
Other Landmarks in Sydney
Sports venues in Sydney
Frequently Asked Questions
Is air quality bad in Hornsby right now?
On 25 August 2026, overall air quality in Hornsby is good. AQI is the main air quality indicator at 14.7/100. Pollution peaks around 11:00 AM (O3: 14.7/100).
Will air quality be worse tomorrow in Hornsby?
On 26 August 2026, air quality conditions in Hornsby will be worse than today, with AQI forecast at fair at 30.9/100. Pollution peaks around 11:00 PM (NO2: 30.9/100).
When is air pollution at its worst in Hornsby?
On Sydney's bushy upper north shore, Hornsby sits closer to extensive bushland than most suburbs, making it more exposed to summer bushfire smoke (December–March) when fires burn nearby. Cold winter nights bring a mild wood-heater haze in this leafy area. Expect sharper seasonal dips here than in harbourside Sydney.
Are air quality levels in Hornsby 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.
Want to see air quality forecasts for other cities in Australia?
Check air quality in other popular cities:
Data provided by Airmine — Last update: 24 August 2026 at 20:27 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.
Get the full experience in the Airmine app.