Air quality
Air quality in Rennes today
Updated
Good (US AQI 27) Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. Model estimate for Mon, Oct 26, 2:00 am (01:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Rennes, Brittany, France, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 27 Good
- PM2.5
- 6.7 µg/m³ 0.4× WHO 24-h guideline
- PM10
- 15 µg/m³
- Ozone
- 45 µg/m³
- Dominant pollutant
- PM2.5 sub-index 27
- Best hour today
- 9:00 pm AQI 28
- European AQI
- 23
Air quality in Rennes right now
Right now the modelled US Air Quality Index for Rennes, Brittany, France is 27, which falls in the "Good" band (up to 50). Air quality is satisfactory and poses little or no risk; a good time for outdoor activity.
The index is driven mainly by PM2.5, whose own sub-index is 27. Fine and coarse particles come from traffic, heating, industry, dust and smoke; they build up on calm nights and clear when wind or rain arrives.
PM2.5 is 6.7 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 15 µg/m³ against a guideline of 45; ozone is 45 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 5.1 µg/m³ (below the 24-hour guideline of 25).
Also this hour: carbon monoxide 170 µg/m³.
Rennes AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 24 around Tue 2:00 am to 31 around Mon 8:00 am, staying "Good" throughout.
The following day looks similar, averaging about 26.
| Local time (Europe/Paris) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Mon 2:00 am | 27 | Good | 6.7 | 15 | 45 |
| Mon 5:00 am | 30 | Good | 4.9 | 12 | 54 |
| Mon 8:00 am | 31 | Good | 3.8 | 8 | 62 |
| Mon 11:00 am | 30 | Good | 4.3 | 8 | 58 |
| Mon 2:00 pm | 30 | Good | 3.9 | 8 | 56 |
| Mon 5:00 pm | 31 | Good | 4.2 | 9 | 49 |
| Mon 8:00 pm | 29 | Good | 4 | 9 | 50 |
| Mon 11:00 pm | 27 | Good | 4.6 | 9 | 52 |
| Tue 2:00 am | 24 | Good | 4.1 | 7 | 52 |
| Tue 5:00 am | 24 | Good | 4.2 | 6 | 54 |
| Tue 8:00 am | 24 | Good | 6.1 | 8 | 45 |
| Tue 11:00 am | 25 | Good | 4 | 9 | 57 |
| Tue 2:00 pm | 25 | Good | 4.1 | 9 | 62 |
| Tue 5:00 pm | 28 | Good | 3.9 | 10 | 67 |
| Tue 8:00 pm | 28 | Good | 7 | 15 | 43 |
| Tue 11:00 pm | 27 | Good | 8.1 | 16 | 37 |
| Wed 2:00 am | 30 | Good | 7.6 | 17 | 38 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in Rennes today
Between 6 am and 9 pm local time, the cleanest air today is forecast around 9:00 pm (AQI 28, Good) and the worst around 8:00 am (AQI 31). The difference across the day is small, so timing matters little.
Rennes vs the rest of France
Across 19 France cities we track, the average US AQI right now is 28 (Good). Rennes at 27 is about average.
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near Rennes
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Laval, Pays de la Loire | 67 km | 25 | Good | 6.3 |
| Nantes | 100 km | 28 | Good | 5.1 |
| Tours | 195 km | 25 | Good | 6.9 |
| Le Havre | 202 km | 35 | Good | 5.5 |
| Orléans, Centre-Val de Loire | 267 km | 27 | Good | 6.5 |
| Dieppe | 284 km | 38 | Good | 4.1 |
| Poole | 290 km | 35 | Good | 3.4 |
| Bournemouth | 291 km | 35 | Good | 3.4 |
Model vs measured
The nearest measured PM2.5 reading is 3.8 µg/m³ from Sensor.Community (median of 24 sensors), centred about 12 km from the city centre. That is close to the model estimate of 6.7 µg/m³. Low-cost sensors can read high in humid air; reference monitors are more accurate but sparser.
Advice for sensitive groups
With the AQI at 27, there is no need for sensitive groups to change plans. People with asthma should still carry their reliever inhaler as usual.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Rennes
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), Sensor.Community.