Air quality comparison · United Kingdom, 49.1 mi (79 km) apart
Cambridge vs London Air quality index (AQI) today
Cambridge has cleaner air than London right now: AQI 48 (Good) against 71 (Moderate).
That puts them in different EPA bands, so the health advice differs today. Over the past 6 days, on modeled daily averages, Cambridge averaged AQI 70 against 81, and it was the cleaner of the two on 5 of those days. Cambridge has lost more forest since 2001. Cambridge has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Cambridge48London71
Head to head
Cambridge vs London at a glance
Cambridge is ahead on 5 of 6 measures, and London on 1. The better figure in each row is marked.
| Cambridge | London | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 48 (better) | 71 |
| PM2.5Fine particles, µg/m³. | 8.7 (better) | 20 |
| Past week's averageUS AQI, 6 days. | 70 (better) | 81 |
| Forest lost since 2001Within 10 km of the center. | 10 ha | 9 ha (better) |
| Tree coverWithin 1.2 mi (2 km) of the center. | 29.7% (better) | 18.4% |
| Trees still neededTo reach a healthy canopy. | 942 (better) | 33.5K |
Air quality today
What is the air like in Cambridge and London right now?
Cambridge has cleaner air than London right now: AQI 48 (Good) against 71 (Moderate). PM2.5 is setting the index in both.
London's PM2.5 is about 1.3× the WHO's 24-hour guideline of 15 µg/m³.
Both readings come from nearby ground stations.
CambridgeLondon
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 6 days?
Over the past 6 days, on modeled daily averages, Cambridge averaged AQI 70 against 81, and it was the cleaner of the two on 5 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
- Cambridge5London1
- Average AQI
- Cambridge70London81
- Worst day, AQI
- Cambridge79London100
The daily numbers (6 days)
| Day | Cambridge | London |
|---|---|---|
| Nov 5 | 40 | 53 |
| Nov 6 | 67 | 89 |
| Nov 7 | 77 | 100 |
| Nov 8 | 77 | 92 |
| Nov 9 | 79 | 82 |
| Nov 10 | 77 | 72 |
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 Cambridge and London today?
Cambridge (AQI 48, Good): Air quality is satisfactory for everyone.
London (AQI 71, Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Exercise outdoors
- Cambridge
- A good day to be active outside.
- London
- Fine for most people; unusually sensitive people should take long or hard exercise easier.
Windows
- Cambridge
- Open them to air the house.
- London
- Fine to open; close them if you are sensitive to pollution.
Masks
- Cambridge
- Not needed.
- London
- Not needed for most people.
Air purifier
- Cambridge
- Not needed.
- London
- Worth running if you are sensitive.
Against everywhere else
How do Cambridge and London compare with the rest of the world?
Right now Cambridge's air is cleaner than 64% of the 5,420 places Airleaf tracks, and London's is cleaner than 37%. Within United Kingdom, that is 65% and 25% of its 92 measured places.
Cleaner air than…
- Cambridge
- Beats 64%
- London
- Beats 37%
More tree cover than…
- Cambridge
- Beats 68%
- London
- Beats 43%
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, Cambridge or London?
Cambridge has lost more: about 10 ha of forest within 10 km of its center from 2001 to 2025, against 9 ha around London. 2 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: 2008, with 2 ha lost.
Worst year: 2008, with 3 ha lost.
| Cambridge | London | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 10 ha | 9 ha (better) |
| Share of its forestOf what it had in 2000. | under 1% | under 1% (better) |
| Cleared for goodTurned into farms, mines or towns. | 2 ha | under 1 ha (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (16%) | Towns and roads (8.9%) |
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.
Cambridge
2018: satellite photo from August 2018 of a 5 × 5 km area in the city center.
London
2017: satellite photo from August 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Cambridge or London?
Cambridge has more tree cover: 29.7% of the land within 1.2 mi (2 km) of its center against 18.4% around London, or about 93,305 trees against 53,065.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Cambridge | London | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 93.3K (better) | 53.1K |
| Trees still neededTo reach the target. Fewer is better. | 942 (better) | 33.5K |
| CO₂ absorbed each yearBy the trees already standing. | 2.1M kg (better) | 1.2M kg |
Tree cover on the satellite image
The same 1.2 mi (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 1.2 mi (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
Cambridge vs London: your questions answered
Is Cambridge cleaner than London?
On air quality, yes, right now: Cambridge reads AQI 48 against 71, a gap of 23 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 6 days, on modeled daily averages, Cambridge averaged AQI 70 against 81, and it was the cleaner of the two on 5 of those days.
Is it safe to exercise outdoors in Cambridge and London today?
In Cambridge, at AQI 48: Air quality is satisfactory for everyone. In London, at AQI 71: Unusually sensitive people should consider limiting long outdoor exertion.
Which has lost more forest, Cambridge or London?
Cambridge has lost more: about 10 ha of forest within 10 km of its center from 2001 to 2025, against 9 ha around London. 2 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Cambridge or London?
Cambridge has more tree cover: 29.7% of the land within 1.2 mi (2 km) of its center against 18.4% around London, or about 93,305 trees against 53,065. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Cambridge and London need?
Cambridge needs about 942 more to reach its canopy target of 30%, and London about 33,454 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Cambridge and London 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 Cambridge vs London 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 (Aug 25, 2026 and Aug 25, 2026), and the forest figures are published yearly.
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