City report · Quebec, Canada
Longueuil Air quality today
Air quality in Longueuil currently reads AQI 14 (Good): Air quality is satisfactory for everyone.
Air quality right now
AQI 14
Good
- PM2.5, fine particles (µg/m³)
- 2.5
- tree cover
- 28.6%
- trees in this area
- 89.8K
- more trees needed
- 4.4K
Measured across a 2 km radius around Le Vieux-Longueuil, Longueuil, QC, Canada (12.57 km²), from a satellite image of Sep 11, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Longueuil · AQI 14 (Good)
Longueuil's tree count comes to 89,850 trees across 12.57 km², 1 points below the 30% tree-cover level considered healthy for this area, so roughly 4,398 more trees would close the gap.
Air quality detail
Air quality in Longueuil today: AQI 14, Good
Main pollutant: PM2.5 · Observed Nov 11, 09:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Longueuil, 2.2 km away · median of 3 stations
Health signal
Air quality is satisfactory for everyone.
PM2.5
2.5
PM10
—
NO₂
9.6
O₃
31.4
SO₂
0.0
CO
—
Data: OpenAQ · AirNow
- Outdoor exercise
- A good day to be active outside
- Windows
- Open them to air the house
- Mask
- Not needed
- Air purifier
- Not needed
Over the last 7 days, the CAMS air-quality model put Longueuil's daily AQI at 39 on average, from 30 on Nov 4 to an hourly peak of 56 on Nov 4.
This is the US EPA AQI. How it differs from Canada's AQHI
Where Longueuil stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Longueuil: Below target
28.6% tree cover against a 30% healthy-neighborhood target, across 12.57 km².
Trees in this area
89,850
Target trees
94,248
More trees needed
4,398
CO₂ if planted / yr
96.8 t
Deforestation · 2001–2025
How much forest has Longueuil lost?
Since 2001, the area within 10 km of Longueuil has lost about 164 hectares of forest (about 230 football pitches): 4.6% of the forest it had in 2000. Most of it (95%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from August 2017 of a 5 × 5 km area about 7 km east of the city center.
- Forest lost since 2001
- 164 haabout 230 football pitches
- Share of its forest
- 4.6%of what there was in 2000
- Cleared for good
- 157 hadeforestation: turned into farms, mines or towns
The worst year was 2018, when about 23 hectares of forest were lost.
Hectares of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 4 ha | 1 ha | 5 ha |
| 2002 | 6 ha | under 1 ha | 6 ha |
| 2003 | 4 ha | under 1 ha | 4 ha |
| 2004 | 6 ha | under 1 ha | 6 ha |
| 2005 | 4 ha | 1 ha | 5 ha |
| 2006 | 2 ha | under 1 ha | 2 ha |
| 2007 | 3 ha | under 1 ha | 3 ha |
| 2008 | 2 ha | under 1 ha | 3 ha |
| 2009 | 3 ha | under 1 ha | 3 ha |
| 2010 | 11 ha | under 1 ha | 11 ha |
| 2011 | 7 ha | under 1 ha | 7 ha |
| 2012 | 5 ha | under 1 ha | 6 ha |
| 2013 | 5 ha | under 1 ha | 5 ha |
| 2014 | 5 ha | under 1 ha | 5 ha |
| 2015 | 9 ha | under 1 ha | 10 ha |
| 2016 | 16 ha | under 1 ha | 16 ha |
| 2017 | 5 ha | under 1 ha | 5 ha |
| 2018 | 23 ha | under 1 ha | 23 ha |
| 2019 | 10 ha | under 1 ha | 11 ha |
| 2020 | 8 ha | under 1 ha | 8 ha |
| 2021 | 5 ha | under 1 ha | 5 ha |
| 2022 | 9 ha | under 1 ha | 9 ha |
| 2023 | 3 ha | under 1 ha | 3 ha |
| 2024 | under 1 ha | under 1 ha | under 1 ha |
| 2025 | 2 ha | under 1 ha | 3 ha |
What is causing deforestation around Longueuil?
- Towns and roadscleared for good85% · 140 ha
- Farms, pasture and plantationscleared for good10% · 17 ha
- Unknown causescause unknown4.5% · 7 ha
Causes for 2025 are estimates, based on what caused forest loss in the same places up to 2024.
Forest gained and lost, 2000–2020
- Forest in 2000
- 7,850 ha
- Forest in 2020
- 8,310 ha
- Overall change
- +463 hamore forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Longueuil grew from about 7,850 hectares to 8,310 hectares, a net gain of about 463 hectares (+5.9%). New forest grew on about 627 hectares, while 164 hectares were lost.
These 2000 and 2020 maps, from the University of Maryland, count any land with trees taller than 5 m as forest, including plantations and orchards. Forest that was cut or burned and had grown back by 2020 counts in both years, so the loss here is smaller than the yearly figures.
These figures cover everything within 10 km of the city center, a wider area than the report above, because forest is usually lost at a city's edges.
Source: Hansen/UMD/Google/USGS/NASA, Global Forest Change (GFC-2025-v1.13); causes: WRI/Google DeepMind drivers of forest loss; both CC BY 4.0, summed by Airleaf for each area. Forest gained and lost 2000–2020: Potapov et al. 2022, UMD GLAD Global Land Cover and Land Use Change, CC BY 4.0. Images: contains modified Copernicus Sentinel data. How it's measured
In the same region
Measured cities near Longueuil
Same 2 km radius, same index — so they compare directly.
- 16.6 km
- Tree cover
- 26%
- Air quality
- 14
- Laval18.5 km
Canada
- Tree cover
- 31%
- Air quality
- 14
- Terrebonne24.8 km
Canada
- Tree cover
- 33%
- Air quality
- 14
- 32.3 km
- Tree cover
- 68%
- Air quality
- 14
- Trois-Rivières116.5 km
Canada
- Tree cover
- 25%
- Air quality
- 11
- Sherbrooke123.0 km
Canada
- Tree cover
- 40%
- Air quality
- 19
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Frequently asked
Questions about Longueuil
What is the air quality (AQI) in Longueuil right now?
The latest reading for Longueuil shows an AQI of 14 (Good), measured Nov 11, 09:00 local time by 3 ground monitoring stations via OpenAQ (the median of their readings; the nearest is Longueuil, 2.2 km away). The main pollutant is PM2.5. Air quality is satisfactory for everyone.
Is it safe to exercise outside in Longueuil today?
At AQI 14 (Good): a good day to be active outside. Windows: open them to air the house. Masks: not needed. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Longueuil been like this week?
Over the last 7 days, the CAMS air-quality model put Longueuil's daily AQI at 39 on average, from 30 on Nov 4 to an hourly peak of 56 on Nov 4. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
Is Longueuil's AQI the same as Canada's AQHI?
No. Airleaf shows the US EPA Air Quality Index (AQI), the scale used by IQAir and most air-quality apps. Canada's Air Quality Health Index (AQHI), from Environment and Climate Change Canada, runs from 1 to 10 and above: 1–3 low risk, 4–6 moderate, 7–10 high and over 10 very high. It combines ozone, nitrogen dioxide and fine particles into one health-risk number, so it isn't a converted AQI, and the two can move differently, especially in wildfire smoke.
How much forest has the area around Longueuil lost since 2001?
Since 2001, the area within 10 km of Longueuil has lost about 164 hectares of forest (about 230 football pitches): 4.6% of the forest it had in 2000. Most of it (95%) was deforestation, forest cleared for good, mainly for towns and roads. Comparing satellite maps from 2000 and 2020, the forest around Longueuil grew from about 7,850 hectares to 8,310 hectares, a net gain of about 463 hectares (+5.9%). New forest grew on about 627 hectares, while 164 hectares were lost.
What is the tree count in Longueuil?
Longueuil has an estimated 89,850 trees across the 12.57 km² measured — 28.6% tree cover, 1 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Longueuil need?
Longueuil needs roughly 4,398 more trees to close a 1-point shortfall against its 30% tree-cover target — about 96.8 t of extra CO₂ absorbed per year once grown.
How are Longueuil's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Le Vieux-Longueuil, via OpenAQ; the 7-day trend is the Open-Meteo / CAMS model's estimate. Tree cover is measured from Sentinel-2 L2A (ESA Copernicus) via Earth Search satellite imagery at 10 m detail across a 2 km radius around Le Vieux-Longueuil; the tree count is an estimate derived from that cover.
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