Country comparison
Nigeria vs United States
Averaged across every city Airleaf has measured in each country — 57 in Nigeria and 308 in United States — each read the same way: Sentinel-2 imagery at 10 m detail over a 2 km radius, and the live US EPA air quality index.
Nigeria averages more tree cover — 33.4% against 29.7%.
United States averages cleaner air — AQI 38 against 52.
- Tree cover gap
- 3.7 points
- Nigeria is ahead.
- Air quality gap
- 14 AQI
- United States is cleaner.
- Cities behind it
- 57 vs 308
- How much each average rests on.
57 cities measured
308 cities measured
Average tree cover
Mean across measured cities, each over the same 2 km radius.
33.4%
29.7%
Average air quality index
US EPA index. Lower is better.
52
38
Cities measured
How much each average rests on.
57
308
Trees still needed
Summed across measured cities, to reach their canopy targets. Fewer is better.
1.1M
7.5M
Behind the averages
The extremes in each country
An average says nothing about how far apart the best and worst places are. These are the measured cities at each end.
United States
- Greenest measured city
- South Fulton98.0% tree cover
- Worst air right now
- StamfordAQI 453
Reading these numbers
What a country average is, and is not
It is a mean of cities
Not a national statistic. Each figure is the average across the cities Airleaf has measured in that country — 57 in Nigeria and 308 in United States — each read over the same 2 km radius. Rural land, forest and everywhere unmeasured are not in it, so this compares urban areas rather than territories.
Coverage shapes the number
A country measured mostly in its capital reads differently from one measured across dozens of towns. United States rests on 308 cities against 57, so its average is the steadier of the two. Both firm up as coverage grows.
Frequently asked
Nigeria and United States, answered
Which country has more tree cover, Nigeria or United States?
Nigeria, averaging 33.4% across its measured cities against 29.7% — a gap of 3.7 percentage points.
Which has cleaner air, Nigeria or United States?
United States, averaging AQI 38 against 52 on the US EPA index. These are live readings averaged across cities, so the gap moves with the weather.
How many cities is each figure based on?
57 measured cities in Nigeria and 308 in United States. Every one was read the same way, so the two averages are directly comparable — but a country with more measured cities has the more settled figure.
Is this the whole country?
No. It is the cities Airleaf has measured, each over a 2 km radius from its centre. Forest, farmland and unmeasured towns are not included, so treat this as a comparison of urban tree cover and urban air rather than of national land cover.
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