Worst air pollution St. Thomas, today and tomorrow
Today (16 July): Air quality in St. Thomas 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: 35.4/100).
Tomorrow (17 July 2026): Air quality in St. Thomas is fair. All pollutants stay as today. Pollution peaks around 10:00 AM (O3: 33.6/100). 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. Thomas' air quality benefits from its inland southwestern Ontario position, with vehicle traffic on Highway 4 the primary local source amid generally good regional wind dispersal.
Today - 16 July | Pollution peaks at 12:00
AQI:
Fair
35.4/100
PM2.5 (fine particles):
Good
8.6/100
PM10 (coarse particles):
Good
7.4/100
NO2 (nitrogen dioxide):
Good
5.6/100
O3 (ozone):
Fair
35.4/100
SO2 (sulfur dioxide):
Good
0.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.6/100
PM1 (ultrafine particles):
Good
3.9/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 10:00
AQI:
Fair
33.6/100
PM2.5 (fine particles):
Good
7.8/100
PM10 (coarse particles):
Good
6.1/100
NO2 (nitrogen dioxide):
Good
4.0/100
O3 (ozone):
Fair
33.6/100
SO2 (sulfur dioxide):
Good
0.8/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.3/100
PM1 (ultrafine particles):
Good
4.4/100
Pollen forecast in St. Thomas
View pollen forecastFrequently Asked Questions
Is air quality bad in St. Thomas right now?
On 16 July 2026, overall air quality in St. Thomas is fair. AQI is the main air quality indicator at 35.4/100. Pollution peaks around 12:00 PM (O3: 35.4/100).
Will air quality be worse tomorrow in St. Thomas?
On 17 July 2026, air quality conditions in St. Thomas will be similar to today, with AQI forecast at fair at 33.6/100. Pollution peaks around 10:00 AM (O3: 33.6/100).
When is air pollution at its worst in St. Thomas?
St. Thomas sees clear seasonal swings in air quality, driven in part by farmland and light manufacturing near Lake Erie. Spring planting and fall harvest can raise dust levels briefly, while summer heat occasionally pushes up ground-level ozone; winter usually brings the cleanest, calmest air of the year. Wind can carry dust well beyond the fields themselves during the busiest planting and harvest weeks.
Are air quality levels in St. Thomas 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