City report · Saga, Japan
Karatsu Air quality today
Air quality in Karatsu currently reads AQI 17 (Good): Air quality is satisfactory for everyone.
Air quality right now
AQI 17
Good
- PM2.5, fine particles (µg/m³)
- 3.5
- tree cover
- 33.9%
- trees in this area
- 90.7K
- more trees needed
- 0
Measured across a 2 km radius around 3 Chome-11 Choda, Karatsu, Saga 847-0821, Japan (12.57 km²), from a satellite image of Sep 22, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Karatsu · AQI 17 (Good)
Karatsu's tree count comes to 90,738 trees across 10.71 km² of land, already at or above the 30% tree-cover level considered healthy for this area.
Air quality detail
Air quality in Karatsu today: AQI 17, Good
Main pollutant: PM2.5 · Observed Nov 11, 12:00 local time via Open-Meteo / CAMS, corrected with 5 ground-station cities within 225 km, US EPA index. Values in µg/m³.
Estimate · model corrected with 5 station cities within 225 km, e.g. Fukuoka and Kasuga
Health signal
Air quality is satisfactory for everyone.
PM2.5
3.5
PM10
17.3
NO₂
7.4
O₃
77.0
SO₂
6.1
CO
186.0
- Outdoor exercise
- A good day to be active outside
- Windows
- Open them to air the house
- Mask
- Not needed
- Air purifier
- Not needed
Over the last 7 days, the CAMS air-quality model put Karatsu's daily AQI at 35 on average, from 23 on Nov 10 to an hourly peak of 78 on Nov 6.
Where Karatsu stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Karatsu: Healthy tree cover
33.9% tree cover against a 30% healthy-neighborhood target, across 10.71 km² of land.
Trees in this area
90,738
Target trees
90,738
More trees needed
0
CO₂ if planted / yr
0 kg
Deforestation · 2001–2025
How much forest has Karatsu lost?
Since 2001, the area within 10 km of Karatsu has lost about 472 hectares of forest (about 660 football pitches): 3.3% of the forest it had in 2000. Most of it (63%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from August 2017 of a 5 × 5 km area about 7 km east of the city center.
- Forest lost since 2001
- 472 haabout 660 football pitches
- Share of its forest
- 3.3%of what there was in 2000
- Cleared for good
- 298 hadeforestation: turned into farms, mines or towns
The worst year was 2007, when about 35 hectares of forest were lost.
Hectares of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 26 ha | 5 ha | 31 ha |
| 2002 | 11 ha | 4 ha | 14 ha |
| 2003 | 11 ha | 5 ha | 16 ha |
| 2004 | 19 ha | 4 ha | 23 ha |
| 2005 | 9 ha | 3 ha | 13 ha |
| 2006 | 19 ha | 6 ha | 24 ha |
| 2007 | 26 ha | 10 ha | 35 ha |
| 2008 | 16 ha | 3 ha | 18 ha |
| 2009 | 12 ha | 2 ha | 13 ha |
| 2010 | 18 ha | 4 ha | 23 ha |
| 2011 | 10 ha | 6 ha | 16 ha |
| 2012 | 13 ha | 12 ha | 25 ha |
| 2013 | 6 ha | 2 ha | 8 ha |
| 2014 | 4 ha | 3 ha | 7 ha |
| 2015 | 8 ha | 8 ha | 16 ha |
| 2016 | 13 ha | 10 ha | 22 ha |
| 2017 | 15 ha | 6 ha | 21 ha |
| 2018 | 7 ha | 11 ha | 18 ha |
| 2019 | 14 ha | 7 ha | 21 ha |
| 2020 | 7 ha | 4 ha | 11 ha |
| 2021 | 7 ha | 11 ha | 19 ha |
| 2022 | 9 ha | 21 ha | 30 ha |
| 2023 | 8 ha | 9 ha | 17 ha |
| 2024 | 6 ha | 6 ha | 12 ha |
| 2025 | 5 ha | 14 ha | 19 ha |
What is causing deforestation around Karatsu?
- Towns and roadscleared for good60% · 285 ha
- Loggingcan grow back31% · 148 ha
- Farms, pasture and plantationscleared for good1.7% · 8 ha
Also: mining and energy, unknown causes.
Causes for 2025 are estimates, based on what caused forest loss in the same places up to 2024.
Forest gained and lost, 2000–2020
- Forest in 2000
- 16,600 ha
- Forest in 2020
- 16,600 ha
- Overall change
- −1 haless forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Karatsu stayed about the same size, at about 16,600 hectares: new forest grew on about 177 hectares, and about 178 hectares were lost.
These 2000 and 2020 maps, from the University of Maryland, count any land with trees taller than 5 m as forest, including plantations and orchards. Forest that was cut or burned and had grown back by 2020 counts in both years, so the loss here is smaller than the yearly figures.
These figures cover everything within 10 km of the city center, a wider area than the report above, because forest is usually lost at a city's edges.
Source: Hansen/UMD/Google/USGS/NASA, Global Forest Change (GFC-2025-v1.13); causes: WRI/Google DeepMind drivers of forest loss; both CC BY 4.0, summed by Airleaf for each area. Forest gained and lost 2000–2020: Potapov et al. 2022, UMD GLAD Global Land Cover and Land Use Change, CC BY 4.0. Images: contains modified Copernicus Sentinel data. How it's measured
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Frequently asked
Questions about Karatsu
What is the air quality (AQI) in Karatsu right now?
The latest reading for Karatsu shows an AQI of 17 (Good), observed Nov 11, 12:00 local time via Open-Meteo / CAMS, corrected with 5 ground-station cities within 225 km, US EPA index. The main pollutant is PM2.5. Air quality is satisfactory for everyone.
Is it safe to exercise outside in Karatsu today?
At AQI 17 (Good): a good day to be active outside. Windows: open them to air the house. Masks: not needed. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Karatsu been like this week?
Over the last 7 days, the CAMS air-quality model put Karatsu's daily AQI at 35 on average, from 23 on Nov 10 to an hourly peak of 78 on Nov 6. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around Karatsu lost since 2001?
Since 2001, the area within 10 km of Karatsu has lost about 472 hectares of forest (about 660 football pitches): 3.3% of the forest it had in 2000. Most of it (63%) was deforestation, forest cleared for good, mainly for towns and roads. Comparing satellite maps from 2000 and 2020, the forest around Karatsu stayed about the same size, at about 16,600 hectares: new forest grew on about 177 hectares, and about 178 hectares were lost.
What is the tree count in Karatsu?
Karatsu has an estimated 90,738 trees across the 10.71 km² of land measured — 33.9% tree cover, already past the 30% tree-cover target set for this area.
How many more trees does Karatsu need?
Karatsu has already reached its tree-cover target, so no additional trees are needed to close the gap.
How are Karatsu's air quality and tree cover measured?
Air quality comes from ground monitoring stations via OpenAQ where one reports nearby, and otherwise, as here, from the Open-Meteo / CAMS model, which may differ from street-level monitors. Tree cover is measured from Sentinel-2 L2A (ESA Copernicus) via Earth Search satellite imagery at 10 m detail across a 2 km radius around 3 Chome-11 Choda; the tree count is an estimate derived from that cover.
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