The whole dataset
Air quality and tree cover, across the whole Earth
An interactive Earth carrying every city Airleaf has measured. Tree cover is read from Sentinel-2 satellite imagery at 10 m detail over a 2 km radius around each city, and air quality is the live US EPA index computed from current pollutant concentrations, measured by ground stations where a city has them and modeled elsewhere. Same index and radius everywhere, so the cities compare directly. A third view wraps the planet in the satellite record of forest lost since 2001. Search for a city to fly straight to it, or read the same figures written out below.
Loading 5,365 cities…
- Cities plotted
- 5,365of 5,423 in the directory
- Countries represented
- 241of 242 with a report page
- Trees behind the lights
- 510.2MEstimated from measured canopy
- Area measured
- 67.4K km²12.6 km² per city, every city the same
How to read the Earth map
Every measured city is a single point of light at the coordinate it was measured at. Two things encode the reading, and both say the same thing in either view: colour tells you the value, and height tells you how far it is from where it should be. Where lights crowd together, that is where people live. The Earth underneath is lit from the sun's real position, so the line between day and night is the one outside your window — which matters, because the air-quality reading is live.
- In the tree-cover view
- Deep green is dense canopy, amber is sparse, rust is close to bare. A city sits higher the less canopy it has, so the brightest, highest lights are the places that have lost their trees — not the ones that kept them. The wash around each city reaches about 150 km, because what was measured is a city, not the farmland beyond it.
- In the air-quality view
- Colours follow the US EPA bands, from green through orange to deep red and purple, and height rises with the index. Here the wash spreads much further, around 780 km, because air moves and a reading over one city says something real about the region around it.
- In the deforestation view
- The planet itself becomes the map: forest cover in 2000 from dark purple (none) to yellow (dense), and forest cut, burned or cleared since 2001 from red for the early years to white for the latest, the same satellite record as the deforestation maps. Cities are white pins, rising with the share of the forest within 10 km that has gone.
- What one light covers
- A 2 km radius around the city centre — about 12.6 km² — not the whole municipality. That is what keeps a small city and a sprawling one comparable. Nothing on the Earth map claims more than that: a country with one measured city shows one light, not a shaded country.
Where the numbers come from
Canopy is measured from Sentinel-2 imagery at 10 m resolution: living leaves reflect near-infrared strongly and absorb red, so the ratio between those bands separates trees from everything else. The tree count is estimated from that cover rather than counted, and each city is re-measured on a rolling schedule.
Air quality is the US EPA index, computed here from pollutant concentrations — PM2.5, PM10, NO₂, ozone, SO₂ and CO — taking the worst single pollutant, as the index is defined. The concentrations come from ground monitoring stations via OpenAQ where a city has any nearby, and from the CAMS model everywhere else, whose PM10 and ozone are shown but left out of the index because the model over-predicts them; a modeled reading can differ from ground-station services.
Questions about the Earth map
- Is the air quality on this Earth map live?
- Yes. Every city's air-quality reading is the current US EPA Air Quality Index, recomputed from up-to-date pollutant concentrations rather than stored once and left. The map genuinely looks different through the day, and the Earth is lit from the sun's real position so you can see which half of the measured world is in daylight.
- Why is my city not on the map?
- The Earth map covers 5,423 cities in 242 countries — essentially every capital plus each country's largest cities, and 300 across the United States. If yours is not among them you can still measure any address yourself on the tree map, which runs a fresh satellite analysis on demand for the exact spot you pick.
- What do the colours on the map mean?
- In the tree-cover view, deep green is dense canopy, amber is sparse and rust is close to bare. In the air-quality view the colours follow the six US EPA bands, from green at Good through orange and red to deep purple at Hazardous. In both views height rises as the reading gets worse, so the brightest, highest points are always the problems.
- Can I see deforestation on the Earth map?
- Yes. The deforestation view wraps the whole planet in the satellite record of forest loss since 2001 (Hansen/UMD Global Forest Change): forest cover in 2000 from dark purple, where there was none, to yellow, where it was dense, and forest cut, burned or cleared since then from red for the early years to white for the latest. Each city is a white pin that rises with the share of the forest within 10 km of it that has gone; select one to see how much was lost and how much of that was cleared for good.
- How is tree cover measured from space?
- From Sentinel-2 satellite imagery at 10 metre resolution. Living leaves reflect near-infrared light strongly and absorb red light, so the ratio between those two bands separates tree canopy from roads, roofs, water and bare ground. Each city is measured over a 2 km radius around its centre — about 12.6 km² — so a small city and a sprawling one stay comparable.
- Why does this differ from other air quality maps?
- Partly because the sources differ. Where ground monitoring stations have reported recently near a city, its reading comes from them via OpenAQ; everywhere else it comes from the CAMS atmospheric model, which covers the whole planet evenly, while station networks are dense in some cities and absent in others. Ground stations measure one street precisely; a model estimates everywhere consistently. Neither is wrong, and they will not always agree.
- Can I reuse this data?
- Yes, under CC BY 4.0. Quote it, chart it or republish it, as long as you credit Airleaf and link back.
Measuring a specific address rather than a city? The tree map runs a fresh satellite analysis on any point you choose. Reusing the readings? CC BY 4.0 — credit Airleaf and link back.
Your own street