Worst air pollution Longueuil, today and tomorrow
Today (16 July): Air quality in Longueuil is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 7:00 AM (O3: 36.7/100).
Tomorrow (17 July 2026): Air quality in Longueuil is fair. All pollutants stay as today. Pollution peaks around 8:00 AM (O3: 30.9/100). 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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Longueuil's air quality reflects its position across the St. Lawrence from Montréal, with vehicle traffic on Highways 20 and 132 contributing local sources amid the broader region's summer ozone.
Today - 16 July | Pollution peaks at 07:00
AQI:
Fair
36.7/100
PM2.5 (fine particles):
Good
5.7/100
PM10 (coarse particles):
Good
2.2/100
NO2 (nitrogen dioxide):
Good
9.1/100
O3 (ozone):
Fair
36.7/100
SO2 (sulfur dioxide):
Good
1.1/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.0/100
PM1 (ultrafine particles):
Good
5.3/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 08:00
AQI:
Fair
30.9/100
PM2.5 (fine particles):
Good
7.1/100
PM10 (coarse particles):
Good
2.6/100
NO2 (nitrogen dioxide):
Good
9.0/100
O3 (ozone):
Fair
30.9/100
SO2 (sulfur dioxide):
Good
0.7/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.9/100
PM1 (ultrafine particles):
Good
6.1/100
Pollen forecast in Longueuil
View pollen forecastAir quality forecasts for neighbourhoods and landmarks in Longueuil
Frequently Asked Questions
Is air quality bad in Longueuil right now?
On 16 July 2026, overall air quality in Longueuil is fair. AQI is the main air quality indicator at 36.7/100. Pollution peaks around 7:00 AM (O3: 36.7/100).
Will air quality be worse tomorrow in Longueuil?
On 17 July 2026, air quality conditions in Longueuil will be similar to today, with AQI forecast at fair at 30.9/100. Pollution peaks around 8:00 AM (O3: 30.9/100).
When is air pollution at its worst in Longueuil?
The air over Longueuil varies through the year, influenced by its dense south-shore streets across the river from downtown Montréal. 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. Its distance from the island's dense core usually keeps conditions a little calmer than central Montréal.
Are air quality levels in Longueuil 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