Worst air pollution St. Catharines, today and tomorrow
Today (16 July): Air quality in St. Catharines is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 11:00 AM (O3: 33.2/100).
Tomorrow (17 July 2026): Air quality in St. Catharines is fair. All pollutants stay as today. Pollution peaks around 8:00 AM (O3: 27.6/100). 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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St. Catharines' air quality benefits from its Niagara Peninsula position between Lake Ontario and the escarpment, with vehicle traffic on the QEW the primary local source amid generally good lake-influenced ventilation.
Today - 16 July | Pollution peaks at 11:00
AQI:
Fair
33.2/100
PM2.5 (fine particles):
Good
7.3/100
PM10 (coarse particles):
Good
4.2/100
NO2 (nitrogen dioxide):
Good
11.0/100
O3 (ozone):
Fair
33.2/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.8/100
PM1 (ultrafine particles):
Good
5.0/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 08:00
AQI:
Fair
27.6/100
PM2.5 (fine particles):
Good
4.7/100
PM10 (coarse particles):
Good
1.8/100
NO2 (nitrogen dioxide):
Good
7.9/100
O3 (ozone):
Fair
27.6/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.9/100
PM1 (ultrafine particles):
Good
3.4/100
Pollen forecast in St. Catharines
View pollen forecastFrequently Asked Questions
Is air quality bad in St. Catharines right now?
On 16 July 2026, overall air quality in St. Catharines is fair. AQI is the main air quality indicator at 33.2/100. Pollution peaks around 11:00 AM (O3: 33.2/100).
Will air quality be worse tomorrow in St. Catharines?
On 17 July 2026, air quality conditions in St. Catharines will be similar to today, with AQI forecast at fair at 27.6/100. Pollution peaks around 8:00 AM (O3: 27.6/100).
When is air pollution at its worst in St. Catharines?
St. Catharines's air quality follows a seasonal rhythm tied to vineyards and orchards of the Niagara fruit belt. Lake breezes off Lake Erie and Lake Ontario generally keep the air clean, though summer heat and cross-border traffic can bring brief periods of smog, and spring brings orchard and field activity. The escarpment and lake together create a moderating effect that keeps extremes fairly rare.
Are air quality levels in St. Catharines 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