Worst air pollution Hamilton, today and tomorrow

Today (9 August): Air quality in Hamilton is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 8:00 AM (O3: 34.6/100).
Tomorrow (10 August 2026): Air quality in Hamilton is fair. All pollutants stay as today. Pollution peaks around 11:00 AM (O3: 31.1/100). Airmine updates local air quality forecasts four times daily.

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Hamilton's air quality reflects its steel-industry legacy on Lake Ontario's harbour, with ArcelorMittal and Stelco operations contributing industrial PM2.5 and SO2 alongside vehicle traffic on the QEW, among Ontario's most industrially affected cities.

Today - 9 August | Pollution peaks at 08:00

AQI:

Fair

34.6/100

PM2.5 (fine particles):

Good

5.0/100

PM10 (coarse particles):

Good

2.1/100

NO2 (nitrogen dioxide):

Good

9.5/100

O3 (ozone):

Fair

34.6/100

SO2 (sulfur dioxide):

Good

0.8/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

6.0/100

PM1 (ultrafine particles):

Good

6.0/100

Levels show the poorest local air quality during the day

Tomorrow - 10 August | Pollution peaks at 11:00

AQI:

Fair

31.1/100

PM2.5 (fine particles):

Good

7.0/100

PM10 (coarse particles):

Good

3.5/100

NO2 (nitrogen dioxide):

Good

14.5/100

O3 (ozone):

Fair

31.1/100

SO2 (sulfur dioxide):

Good

0.8/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

6.5/100

PM1 (ultrafine particles):

Good

6.1/100

Pollen forecast in Hamilton

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Air quality forecasts for neighbourhoods and landmarks in Hamilton

Sports venues in Hamilton

Frequently Asked Questions

Is air quality bad in Hamilton right now?

On 9 August 2026, overall air quality in Hamilton is fair. AQI is the main air quality indicator at 34.6/100. Pollution peaks around 8:00 AM (O3: 34.6/100).

Will air quality be worse tomorrow in Hamilton?

On 10 August 2026, air quality conditions in Hamilton will be similar to today, with AQI forecast at fair at 31.1/100. Pollution peaks around 11:00 AM (O3: 31.1/100).

When is air pollution at its worst in Hamilton?

Hamilton's air quality follows a seasonal rhythm tied to its steel mills along the harbourfront and the Niagara Escarpment above the city. Air quality here tends to dip in summer, when heat and industrial output combine, and again briefly in winter when cold, calm air traps emissions near ground level. Residents closer to the industrial waterfront tend to notice the seasonal swing more sharply than those higher up the escarpment.

Are air quality levels in Hamilton 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: 9 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.

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