Air quality comparison · Canada, 164 km apart
London vs Windsor Air quality index (AQI) today
London has cleaner air than Windsor right now: AQI 62 (Moderate) against 68 (Moderate).
Both sit in the same EPA band, so the health advice is the same for each today. Over the past 7 days, on modeled daily averages, London averaged AQI 18 against 28, and it was the cleaner of the two on 6 of those days. London has lost more forest since 2001. London has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
London62Windsor68
Head to head
London vs Windsor at a glance
London is ahead on 5 of 6 measures, and Windsor on 1. The better figure in each row is marked.
| London | Windsor | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 62 (better) | 68 |
| PM2.5Fine particles, µg/m³. | 15 (better) | 18.4 |
| Past week's averageUS AQI, 7 days. | 18 (better) | 28 |
| Forest lost since 2001Within 10 km of the center. | 153 ha | 40 ha (better) |
| Tree coverWithin 2 km of the center. | 31.4% (better) | 25.6% |
| Trees still neededTo reach a healthy canopy. | 0 (better) | 13.7K |
Air quality today
What is the air like in London and Windsor right now?
London has cleaner air than Windsor right now: AQI 62 (Moderate) against 68 (Moderate). PM2.5 is setting the index in both.
Windsor's PM2.5 is about 1.2× the WHO's 24-hour guideline of 15 µg/m³.
Both readings come from nearby ground stations.
LondonWindsor
Concentrations at the same moment as the index above, for the pollutants both places report. Lower is better. The dark marks on the PM2.5 and PM10 rows show the WHO's 24-hour guidelines (15 and 45 µg/m³).
The past week
Which had cleaner air over the past 7 days?
Over the past 7 days, on modeled daily averages, London averaged AQI 18 against 28, and it was the cleaner of the two on 6 of those days. A single reading can catch a city on a bad afternoon; the week says whether it was the weather or the place.
- Cleaner days
- London6Windsor1
- Average AQI
- London18Windsor28
- Worst day, AQI
- London38Windsor39
The daily numbers (7 days)
| Day | London | Windsor |
|---|---|---|
| Nov 4 | 19 | 23 |
| Nov 5 | 19 | 28 |
| Nov 6 | 13 | 18 |
| Nov 7 | 15 | 22 |
| Nov 8 | 38 | 34 |
| Nov 9 | 11 | 39 |
| Nov 10 | 14 | 34 |
Daily averages from the CAMS atmospheric model for both places, so the week compares like with like. They can differ from today's reading at the top of the page wherever that comes from a ground station.
What it means today
Is it safe to go outside in London and Windsor today?
Unusually sensitive people should consider limiting long outdoor exertion. Both are in the same EPA band today (Moderate), so the advice is the same.
Exercise outdoors
Fine for most people; unusually sensitive people should take long or hard exercise easier.
Windows
Fine to open; close them if you are sensitive to pollution.
Masks
Not needed for most people.
Air purifier
Worth running if you are sensitive.
Against everywhere else
How do London and Windsor compare with the rest of the world?
Right now London's air is cleaner than 46% of the 5,420 places Airleaf tracks, and Windsor's is cleaner than 40%. Within Canada, that is 7% and 2% of its 59 measured places.
Cleaner air than…
- London
- Beats 46%
- Windsor
- Beats 40%
More tree cover than…
- London
- Beats 71%
- Windsor
- Beats 59%
Includes model estimates as well as station readings, so it can differ from our most polluted and cleanest air rankings, which use station readings only.
Deforestation · 2001–2025
Which has lost more forest, London or Windsor?
London has lost more: about 153 ha of forest within 10 km of its center from 2001 to 2025, against 40 ha around Windsor. 136 ha of that was cleared for good, for farms, mines or towns.
Measured within 10 km of each center, from the yearly satellite maps of forest loss: a wider circle than the one for tree cover, because forest is usually lost at a city's edges.
Worst year: 2017, with 17 ha lost.
Worst year: 2012, with 11 ha lost.
| London | Windsor | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 153 ha | 40 ha (better) |
| Share of its forestOf what it had in 2000. | 3.8% | 2.3% (better) |
| Cleared for goodTurned into farms, mines or towns. | 136 ha | 33 ha (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (79%) | Towns and roads (72%) |
Satellite timelapses
Watch both change, year by year
A clear satellite photo a year of the land around each city. Press play, turn on the forest cleared since the first year, or drag the before and after.
London
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
Windsor
2017: satellite photo from July 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, London or Windsor?
London has more tree cover: 31.4% of the land within 2 km of its center against 25.6% around Windsor, or about 98,646 trees against 79,942.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| London | Windsor | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 98.6K (better) | 79.9K |
| Trees still neededTo reach the target. Fewer is better. | 0 (better) | 13.7K |
| CO₂ absorbed each yearBy the trees already standing. | 2.2M kg (better) | 1.8M kg |
Tree cover on the satellite image
The same 2 km radius around each center, with the tree cover the satellite found marked on it.
Reading these numbers
How this comparison is made
Air quality index
The US EPA index, computed from current pollutant concentrations: ground stations where a place has them nearby, and the CAMS atmospheric model everywhere else. It moves hour to hour, so it is a snapshot rather than a verdict on either place. The guideline marks are from the WHO's 2021 air quality guidelines.
Trees and forest
Tree cover is the share of ground under canopy within 2 km of each center, read from Sentinel-2 satellite imagery at 10 m detail. It measures that circle, not the whole municipality, which is what makes the two comparable. Forest loss comes from the University of Maryland's Global Forest Change maps.
More on the method on the About Airleaf page.
Frequently asked
London vs Windsor: your questions answered
Is London cleaner than Windsor?
On air quality, yes, right now: London reads AQI 62 against 68, a gap of 6 points on the US EPA index. This is a live reading rather than an annual average, so it can reverse within a day. Over the past 7 days, on modeled daily averages, London averaged AQI 18 against 28, and it was the cleaner of the two on 6 of those days.
Is it safe to exercise outdoors in London and Windsor today?
The advice is the same for both today. Unusually sensitive people should consider limiting long outdoor exertion. London reads AQI 62 and Windsor reads AQI 68.
Which has lost more forest, London or Windsor?
London has lost more: about 153 ha of forest within 10 km of its center from 2001 to 2025, against 40 ha around Windsor. 136 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, London or Windsor?
London has more tree cover: 31.4% of the land within 2 km of its center against 25.6% around Windsor, or about 98,646 trees against 79,942. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do London and Windsor need?
London needs about 0 more to reach its canopy target of 30%, and Windsor about 13,740 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are London and Windsor measured the same way?
The method is the same: the US EPA index for air, and Sentinel-2 satellite imagery at 10 m detail over an identical radius for trees. Both readings come from nearby ground stations. Nothing is adjusted for population, city limits or climate.
How often does the London vs Windsor comparison update?
The air readings refresh about once an hour, and each reading's local time is shown at the top of the page. Tree cover comes from the latest clear satellite image of each area (Sep 10, 2026 and Aug 28, 2026), and the forest figures are published yearly.
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