Where the data comes from
The data is the European air quality forecast of the Copernicus Atmosphere Monitoring Service (CAMS), the service of the European Union's Copernicus programme operated by the European Centre for Medium-Range Weather Forecasts (ECMWF). It is open and free data, downloaded from the Atmosphere Data Store.
Which forecast we use
- "Ensemble" model: not a single model, but the combination (median) of the forecasts of about ten European models. It is the most robust version CAMS provides.
- Resolution: one cell every 0.1 degrees, i.e. about 11 km north-south and 7–9 km east-west at Italian latitudes. Each cell has a single value: differences within the cell (a street, a park) are not visible.
- Area covered: all of Europe, from North Africa to Scandinavia.
- Level: values refer to the air near the ground, the air we breathe.
- Unit: micrograms per cubic metre (µg/m³), hourly values.
Pollutants and thresholds
For each pollutant the map compares the value with a reference threshold: below the threshold colours go from cyan to green, at the threshold they turn yellow, above it they move to red and, above twice the threshold, to purple.
| Pollutant | Threshold |
|---|---|
| Fine particulate matter (PM2.5) | 25 µg/m³ |
| Particulate matter (PM10) | 45 µg/m³ |
| Nitrogen dioxide (NO₂) | 50 µg/m³ |
| Ozone (O₃) | 120 µg/m³ |
| Sulphur dioxide (SO₂) | 50 µg/m³ |
The thresholds are the limits of European legislation in force from 2030 (Directive 2024/2881): the daily limits for particulate matter, nitrogen dioxide and sulphur dioxide, and the target value for ozone (average over 8 hours). They are the strictest European references, chosen on purpose: the hourly limits for NO₂ and SO₂ only flag acute episodes, while this site wants to make everyday exposure visible. The limits apply to the average of a whole day (or of 8 hours), while the map shows the value of a single hour: the comparison is indicative, not a check of compliance with legal limits.
Why the ozone map is coloured almost everywhere. Ozone is not emitted directly: it forms in the air from other pollutants under sunlight and spreads over large areas, also far from cities. Across Europe there is a widespread background of roughly 60–100 µg/m³, so the ozone map often shows green to yellow over the whole continent, without the clean areas and local hotspots seen for the other pollutants. It is not an error: it is the real picture, and in summer, with stronger sunlight, values above the threshold become common in many areas.
European Air Quality Index (EEA)
The ranking and the charts also show the European Air Quality Index of the European Environment Agency, in the version revised in 2024 on the basis of the 2021 World Health Organization guidelines. Each pollutant gets a level from its hourly value, and the index is the worst level among the pollutants: it does not add them up.
| µg/m³ | Good | Fair | Moderate | Poor | Very poor | Extremely poor |
|---|---|---|---|---|---|---|
| Fine particulate matter (PM2.5) | 0–5 | 6–15 | 16–50 | 51–90 | 91–140 | >140 |
| Particulate matter (PM10) | 0–15 | 16–45 | 46–120 | 121–195 | 196–270 | >270 |
| Nitrogen dioxide (NO₂) | 0–10 | 11–25 | 26–60 | 61–100 | 101–150 | >150 |
| Ozone (O₃) | 0–60 | 61–100 | 101–120 | 121–160 | 161–180 | >180 |
| Sulphur dioxide (SO₂) | 0–20 | 21–40 | 41–125 | 126–190 | 191–275 | >275 |
Here the index is computed on the average of the area shown (the same as the charts), hour by hour. In the ranking each place shows the worst hour of the day (00–24 UTC); places at the same level are ordered by the average of the hourly levels. The EEA computes the index on measuring stations: here it is applied to the CAMS forecast, so it is an estimate. Source: ETC HE Report 2024/17.
Credits
Generated using Copernicus Atmosphere Monitoring Service information (2026). Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains. Basemaps: OpenFreeMap © OpenMapTiles, data © OpenStreetMap contributors.