Country comparison
Japan vs Tanzania
Averaged across every city Airleaf has measured in each country — 207 in Japan and 34 in Tanzania — 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.
Japan averages more tree cover — 28.5% against 18.9%.
Japan averages cleaner air — AQI 29 against 41.
- Tree cover gap
- 9.5 points
- Japan is ahead.
- Air quality gap
- 12 AQI
- Japan is cleaner.
- Cities behind it
- 207 vs 34
- How much each average rests on.
Average tree cover
Mean across measured cities, each over the same 2 km radius.
28.5%
18.9%
Average air quality index
US EPA index. Lower is better.
29
41
Cities measured
How much each average rests on.
207
34
Trees standing
Summed across every measured city in each country.
17.9M
1.9M
Cities below their target
Share of measured cities short of the canopy target. Lower is better.
62% (129)
82% (28)
Trees still needed
Summed across measured cities, to reach their canopy targets. Fewer is better.
4.5M
1.6M
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.
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 — 207 in Japan and 34 in Tanzania — 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. Japan rests on 207 cities against 34, so its average is the steadier of the two. Both firm up as coverage grows.
Frequently asked
Japan and Tanzania, answered
Which country has more tree cover, Japan or Tanzania?
Japan, averaging 28.5% across its measured cities against 18.9% — a gap of 9.5 percentage points.
Which has cleaner air, Japan or Tanzania?
Japan, averaging AQI 29 against 41 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?
207 measured cities in Japan and 34 in Tanzania. 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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