Air quality comparison · France, 100 km apart
Nantes vs Rennes Air quality index (AQI) today
Rennes has cleaner air than Nantes right now: AQI 39 (Good) against 43 (Good).
Both sit in the same EPA band, so the health advice is the same for each today. But over the past 5 days, on modeled daily averages, Nantes averaged AQI 63 against 66, and it was the cleaner of the two on 5 of those days. Nantes has lost more forest since 2001. Rennes has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Nantes43Rennes39
Head to head
Nantes vs Rennes at a glance
Rennes is ahead on 5 of 6 measures, and Nantes on 1. The better figure in each row is marked.
| Nantes | Rennes | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 43 | 39 (better) |
| PM2.5Fine particles, µg/m³. | 7.7 | 7.1 (better) |
| Past week's averageUS AQI, 5 days. | 63 (better) | 66 |
| Forest lost since 2001Within 10 km of the center. | 71 ha | 51 ha (better) |
| Tree coverWithin 2 km of the center. | 21.8% | 27.8% (better) |
| Trees still neededTo reach a healthy canopy. | 24.2K | 6.9K (better) |
Air quality today
What is the air like in Nantes and Rennes right now?
Rennes has cleaner air than Nantes right now: AQI 39 (Good) against 43 (Good). PM2.5 is setting the index in both.
Both readings come from nearby ground stations.
NantesRennes
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).
Nantes: Ground station · Freres Goncourt, Nantes, Loire, France, 2 km away · median of 2 stations. Data: World Air Quality Index Project, Air Pays de la Loire.
Rennes: Ground station · Rennes Laennec, 700 m away · median of 3 stations. Data: OpenAQ · EEA.
The past week
Which had cleaner air over the past 5 days?
But over the past 5 days, on modeled daily averages, Nantes averaged AQI 63 against 66, 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
- Nantes5Rennes0
- Average AQI
- Nantes63Rennes66
- Worst day, AQI
- Nantes71Rennes73
The daily numbers (5 days)
| Day | Nantes | Rennes |
|---|---|---|
| Nov 5 | 65 | 69 |
| Nov 6 | 71 | 73 |
| Nov 7 | 67 | 71 |
| Nov 8 | 61 | 62 |
| Nov 9 | 49 | 57 |
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 Nantes and Rennes today?
Air quality is satisfactory for everyone. Both are in the same EPA band today (Good), so the advice is the same.
Exercise outdoors
A good day to be active outside.
Windows
Open them to air the house.
Masks
Not needed.
Air purifier
Not needed.
Against everywhere else
How do Nantes and Rennes compare with the rest of the world?
Right now Nantes's air is cleaner than 68% of the 5,420 places Airleaf tracks, and Rennes's is cleaner than 71%. Within France, that is 34% and 42% of its 39 measured places.
Cleaner air than…
- Nantes
- Beats 68%
- Rennes
- Beats 71%
More tree cover than…
- Nantes
- Beats 51%
- Rennes
- Beats 64%
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, Nantes or Rennes?
Nantes has lost more: about 71 ha of forest within 10 km of its center from 2001 to 2025, against 51 ha around Rennes. 45 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: 2021, with 16 ha lost.
Worst year: 2010, with 10 ha lost.
| Nantes | Rennes | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 71 ha | 51 ha (better) |
| Share of its forestOf what it had in 2000. | 1.3% (better) | 1.9% |
| Cleared for goodTurned into farms, mines or towns. | 45 ha | 4 ha (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (48%) | Logging (66%) |
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.
Nantes
2017: satellite photo from July 2017 of a 5 × 5 km area in the city center.
Rennes
2017: satellite photo from July 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Nantes or Rennes?
Rennes has more tree cover: 27.8% of the land within 2 km of its center against 21.8% around Nantes, or about 87,249 trees against 64,241.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Nantes | Rennes | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 64.2K | 87.2K (better) |
| Trees still neededTo reach the target. Fewer is better. | 24.2K | 6.9K (better) |
| CO₂ absorbed each yearBy the trees already standing. | 1.4M kg | 1.9M kg (better) |
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
Nantes vs Rennes: your questions answered
Is Rennes cleaner than Nantes?
On air quality, yes, right now: Rennes reads AQI 39 against 43, a gap of 4 points on the US EPA index. This is a live reading rather than an annual average, so it can reverse within a day. But over the past 5 days, on modeled daily averages, Nantes averaged AQI 63 against 66, and it was the cleaner of the two on 5 of those days.
Is it safe to exercise outdoors in Nantes and Rennes today?
The advice is the same for both today. Air quality is satisfactory for everyone. Nantes reads AQI 43 and Rennes reads AQI 39.
Which has lost more forest, Nantes or Rennes?
Nantes has lost more: about 71 ha of forest within 10 km of its center from 2001 to 2025, against 51 ha around Rennes. 45 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Nantes or Rennes?
Rennes has more tree cover: 27.8% of the land within 2 km of its center against 21.8% around Nantes, or about 87,249 trees against 64,241. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Nantes and Rennes need?
Nantes needs about 24,164 more to reach its canopy target of 30%, and Rennes about 6,905 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Nantes and Rennes 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 Nantes vs Rennes 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 24, 2026 and Sep 22, 2026), and the forest figures are published yearly.
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