Cartagena vs Castelló de la Plana
Tree cover and air quality for both, measured the same way: Sentinel-2 imagery at 10 m detail over a 2 km radius from each city centre, and the live US EPA air quality index. Same radius and same index, so the two numbers compare directly.
Castelló de la Plana has more tree cover — 11.0% against 5.2%.
Cartagena has cleaner air right now — AQI 31 against 50.
- Tree cover gap
- 5.8 points
- Castelló de la Plana is ahead.
- Air quality gap
- 19 AQI
- Cartagena is cleaner.
- Trees between them
- 20.7K
- Castelló de la Plana has more standing.
Spain
Spain
Tree cover
Share of the 2 km radius under canopy.
5.2%
11.0%
Air quality index
US EPA index, live, with its band. Lower is better.
31 · Good
50 · Good
Trees standing
Estimated from the measured canopy area.
13.9K
34.6K
Trees still needed
To reach the same canopy target. Fewer is better.
66.3K
59.7K
CO₂ absorbed each year
By the trees already standing.
306K kg
760K kg
Air quality in detail
What each city is breathing
Concentrations in µg/m³, measured at the same moment as the index above. Lower is better in every row. Castelló de la Plana is read from nearby ground stations and Cartagena is modelled — worth knowing, since the two are not quite like for like.
PM2.5
Fine particles, the pollutant that usually sets the index.
5.4 µg/m³
12 µg/m³
PM10
Coarser particles — dust, pollen, road grit.
10.4 µg/m³
7 µg/m³
Nitrogen dioxide
Mostly traffic and combustion.
5 µg/m³
38 µg/m³
Ozone
Forms in sunlight; peaks on hot, still afternoons.
77 µg/m³
10 µg/m³
The last week, day by day
A single reading can catch a city on a bad afternoon. The week says whether it was the weather or the place.
| Day | Cartagena | Castelló de la Plana |
|---|---|---|
| 22 Sept | 37 | 34 |
| 23 Sept | 37 | 40 |
| 24 Sept | 35 | 44 |
| 25 Sept | 40 | 45 |
| 26 Sept | 45 | 46 |
| 27 Sept | 37 | 40 |
| 28 Sept | 34 | 37 |
Reading these numbers
What is actually being measured
Tree cover
The share of ground under canopy inside a 2 km radius of each city centre, read from Sentinel-2 satellite imagery at 10 m detail. It is a measurement of that circle, not of the whole municipality — which is exactly what makes the two comparable, since city boundaries are drawn to wildly different rules around the world. Castelló de la Plana leads here at 11.0%.
Air quality index
The live US EPA index, computed from current pollutant concentrations — ground stations where a city has them nearby, and a model everywhere else. It moves hour to hour, so this is a snapshot rather than a verdict on either place: Cartagena reads 31 (good) and Castelló de la Plana reads 50 (good) right now.
Frequently asked
Cartagena and Castelló de la Plana, answered
Which has more trees, Cartagena or Castelló de la Plana?
Castelló de la Plana, with roughly 34,558 trees inside its 2 km radius against 13,902. Tree cover tells a slightly different story from raw count: Castelló de la Plana has the denser canopy at 11.0%.
Which has better air quality, Cartagena or Castelló de la Plana?
Cartagena right now, at AQI 31 against 50 — a gap of 19 points. This is a live reading rather than an annual average, so it can reverse within a day.
How many more trees does each city need?
Cartagena needs about 66,303 more to reach its canopy target, and Castelló de la Plana about 59,690. The target is the same share of ground for both, so the figures are directly comparable.
Are these two measured the same way?
Yes — that is the point of the page. Identical radius, identical satellite source at 10 m detail, and the same US EPA index for air. Nothing here is adjusted for population, city limits or climate, so the numbers describe the same-sized circle of ground in each place.
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