Worst air pollution Thornhill - Vaughan, today and tomorrow
Today (10 August): Air quality in Thornhill is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 12:00 PM (O3: 33.2/100).
Tomorrow (11 August 2026): Air quality in Thornhill is fair. NO2 increases to fair; PM1 increases to fair; all other pollutants stay as today. Pollution peaks around 10:00 AM (O3: 36.9/100). Airmine updates local air quality forecasts four times daily.
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Thornhill's air quality reflects its position in the northern Greater Toronto Area, with vehicle traffic on Highway 407 the primary local source amid the region's broader summer ozone challenges.
Today - 10 August | Pollution peaks at 12:00
AQI:
Fair
33.2/100
PM2.5 (fine particles):
Good
17.4/100
PM10 (coarse particles):
Good
7.0/100
NO2 (nitrogen dioxide):
Good
14.7/100
O3 (ozone):
Fair
33.2/100
SO2 (sulfur dioxide):
Good
2.1/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
9.4/100
PM1 (ultrafine particles):
Good
18.8/100
Levels show the poorest local air quality during the day
Tomorrow - 11 August | Pollution peaks at 10:00
AQI:
Fair
36.9/100
PM2.5 (fine particles):
Good
19.2/100
PM10 (coarse particles):
Good
7.0/100
NO2 (nitrogen dioxide):
Fair
33.2/100
O3 (ozone):
Fair
36.9/100
SO2 (sulfur dioxide):
Good
2.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
16.4/100
PM1 (ultrafine particles):
Fair
21.4/100
Other Landmarks in Vaughan
Sports venues in Vaughan
Frequently Asked Questions
Is air quality bad in Thornhill right now?
On 10 August 2026, overall air quality in Thornhill is fair. AQI is the main air quality indicator at 33.2/100. Pollution peaks around 12:00 PM (O3: 33.2/100).
Will air quality be worse tomorrow in Thornhill?
On 11 August 2026, air quality conditions in Thornhill will be similar to today, with AQI forecast at fair at 36.9/100. Pollution peaks around 10:00 AM (O3: 36.9/100).
When is air pollution at its worst in Thornhill?
The air over Thornhill varies through the year, influenced by its dense suburban streets straddling the Toronto-Vaughan boundary. The warmest months typically see the poorest air quality, with heat and heavy traffic driving up smog levels on windless days, whereas fall and winter tend to bring cleaner, more variable conditions. Because the area sits downwind of denser Toronto traffic, conditions can still worsen on hot, windless afternoons.
Are air quality levels in Thornhill 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: 10 August 2026 at 08:45 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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