Worst air pollution Mount St. Louis Moonstone - Barrie, today and tomorrow
Today (20 September): Air quality in Mount St. Louis Moonstone 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: 21.7/100).
Tomorrow (21 September 2026): Air quality in Mount St. Louis Moonstone is good. AQI improves to good; O3 decreases to good; all other pollutants stay as today. Pollution peaks around 8:00 AM (O3: 17.9/100). Airmine updates local air quality forecasts four times daily.
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Mount St. Louis Moonstone's air quality benefits from its rural position near Coldwater, with winter ski tourism traffic the primary seasonal local source amid otherwise clean rural conditions.
Today - 20 September | Pollution peaks at 12:00
AQI:
Fair
21.7/100
PM2.5 (fine particles):
Good
10.7/100
PM10 (coarse particles):
Good
9.9/100
NO2 (nitrogen dioxide):
Good
6.4/100
O3 (ozone):
Fair
21.7/100
SO2 (sulfur dioxide):
Good
0.3/100
CO (carbon monoxide):
Good
0.6/100
HCHO (formaldehyde):
Good
4.6/100
PM1 (ultrafine particles):
Good
2.8/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 08:00
AQI:
Good
17.9/100
PM2.5 (fine particles):
Good
11.2/100
PM10 (coarse particles):
Good
10.8/100
NO2 (nitrogen dioxide):
Good
8.0/100
O3 (ozone):
Good
17.9/100
SO2 (sulfur dioxide):
Good
0.4/100
CO (carbon monoxide):
Good
0.6/100
HCHO (formaldehyde):
Good
4.8/100
PM1 (ultrafine particles):
Good
2.8/100
Other Landmarks in Barrie
Sports venues in Barrie
Frequently Asked Questions
Is air quality bad in Mount St. Louis Moonstone right now?
On 20 September 2026, overall air quality in Mount St. Louis Moonstone is fair. AQI is the main air quality indicator at 21.7/100. Pollution peaks around 12:00 PM (O3: 21.7/100).
Will air quality be worse tomorrow in Mount St. Louis Moonstone?
On 21 September 2026, air quality conditions in Mount St. Louis Moonstone will be better than today, with AQI forecast at good at 17.9/100. Pollution peaks around 8:00 AM (O3: 17.9/100).
When is air pollution at its worst in Mount St. Louis Moonstone?
Mount St. Louis Moonstone sees clear seasonal swings in air quality, driven in part by its ski hills set in the snowbelt north of Barrie. The nearby lake keeps summer air relatively clean and fresh, while winter's lake-effect systems bring heavy snow squalls that periodically reduce visibility rather than pollution levels. Air pollution levels themselves stay comparatively low year-round, even when the weather itself turns severe.
Are air quality levels in Mount St. Louis Moonstone 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: 20 September 2026 at 14:33 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.
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.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
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