Is the air quality good in Montreal?
On September 23, 2025, 7:05 AM PT, Montreal, Canada's air quality is ranked as "moderate." The city is currently ranked as the 9th most polluted major city in the world.
Click here for a real-time air quality map of Montreal.
While the air quality conditions in Montreal are poor, it is important to keep in mind that the average PM2.5 concentration in 2024 for Montreal was 8.9 µg/m3. This corresponds to an AQI of 49, which falls into the “moderate” category and was 1.8 times the WHO annual guideline of 5 µg/m3.
Montreal, Canada ranked as the 9th most polluted major city as of 7:05 AM PT on Sept 23, 2025. Source: IQAir.
When will air quality improve in Montreal?
Forecasts suggest that air quality may improve later in the day as meteorological conditions shift.
Hourly air quality forecast for Montreal, Canada on Sept 23, 2025. Source: IQAir.
Wind speed and changes in atmospheric pressure, plus more pollutant dispersion could be factors in reducing pollution levels later in the day.
Air quality map of Montreal, Canada on Sept 23, 2025. Source: IQAir.
What is causing poor air quality in Montreal?
Wildfire smoke can be a significant source of poor air quality in Montreal. However, as of Tuesday morning, there isn't a lot of wildfire smoke in the city.
Poor air quality in Montreal is usually caused by vehicle emissions, construction dust, and both agricultural and industrial pollution (1). Transboundary pollution from the United States can be a significant source of poor air quality as well.
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How can I protect myself from poor air quality?
- Get a free air quality app for real-time air quality alerts and forecasts.
- Shut doors and windows and set the HVAC to recirculate mode.
- Contribute to your community’s outdoor air quality data.
- Stay indoors when air quality is poor; if you do need to go outdoors, wear a KN95/FFP2 mask.
- Run a high-performance air purifier to filter particles, gases, and other pollutants.
