Worst air pollution Guelph, today and tomorrow
Today (16 July): Air quality in Guelph is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 10:00 AM (O3: 32.0/100).
Tomorrow (17 July 2026): Air quality in Guelph is fair. All pollutants stay as today. Pollution peaks around 8:00 AM (O3: 29.1/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Guelph's air quality benefits from its inland Speed River valley position, with vehicle traffic on the 401 the primary local source amid generally good southwestern Ontario wind dispersal.
Today - 16 July | Pollution peaks at 10:00
AQI:
Fair
32.0/100
PM2.5 (fine particles):
Good
9.2/100
PM10 (coarse particles):
Good
5.9/100
NO2 (nitrogen dioxide):
Good
12.0/100
O3 (ozone):
Fair
32.0/100
SO2 (sulfur dioxide):
Good
1.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
4.3/100
PM1 (ultrafine particles):
Good
6.3/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 08:00
AQI:
Fair
29.1/100
PM2.5 (fine particles):
Good
7.1/100
PM10 (coarse particles):
Good
2.8/100
NO2 (nitrogen dioxide):
Good
12.3/100
O3 (ozone):
Fair
29.1/100
SO2 (sulfur dioxide):
Good
1.8/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.0/100
PM1 (ultrafine particles):
Good
5.1/100
Pollen forecast in Guelph
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Frequently Asked Questions
Is air quality bad in Guelph right now?
On 16 July 2026, overall air quality in Guelph is fair. AQI is the main air quality indicator at 32.0/100. Pollution peaks around 10:00 AM (O3: 32.0/100).
Will air quality be worse tomorrow in Guelph?
On 17 July 2026, air quality conditions in Guelph will be similar to today, with AQI forecast at fair at 29.1/100. Pollution peaks around 8:00 AM (O3: 29.1/100).
When is air pollution at its worst in Guelph?
The air over Guelph varies through the year, influenced by its compact downtown ringed by farmland and light manufacturing. 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. Local monitoring stations typically flag the sharpest changes during still, hot afternoons in July and August.
Are air quality levels in Guelph 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.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 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.
For long term forecasts and maps, see the Airmine app