City report · Ehime, Japan
Saijō Air quality today
Air quality in Saijō currently reads AQI 28 (Good): Air quality is satisfactory for everyone.
AQI 28
Air quality right now
Good
- PM2.5, fine particles (µg/m³)
- 5.0
- tree cover
- 6.8%
- trees in this area
- 21.0K
- more trees needed
- 71.6K
Measured across a 2 km radius around Omachi, Saijo, Ehime 793-0030, Japan (12.57 km²), from a satellite image of Aug 25, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Saijō · AQI 28 (Good)
Saijō's tree count comes to 20,978 trees across 12.34 km² of land, 23 points below the 30% tree-cover level considered healthy for this area, so roughly 71,573 more trees would close the gap.
Air quality detail
Air quality in Saijō today: AQI 28, Good
Main pollutant: PM2.5 · Observed Nov 12, 00:00 local time via World Air Quality Index Project ground stations, US EPA index. Values in µg/m³.
Ground station · Asahimachi, Imabari, Ehime, Japan (今治旭今治市), 23.5 km away
Health signal
Air quality is satisfactory for everyone.
PM2.5
5.0
PM10
7.6
NO₂
—
O₃
—
SO₂
—
CO
—
Data: World Air Quality Index Project, Japan Atmospheric Environmental Regional Observation System (環境省大気汚染物質広域監視システム)
- 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 Saijō's daily AQI at 36 on average, from 25 on Nov 10 to an hourly peak of 68 on Nov 6.
Where Saijō stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Saijō: Critically low
6.8% tree cover against a 30% healthy-neighborhood target, across 12.34 km² of land.
Trees in this area
20,978
Target trees
92,551
More trees needed
71,573
CO₂ if planted / yr
1,575 t
Deforestation · 2001–2025
How much forest has Saijō lost?
Since 2001, the area within 10 km of Saijō has lost about 263 hectares of forest (about 370 football pitches): 2.2% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 29 hectares (11%) was deforestation: forest cleared for good for farms, mines or towns.
2017: satellite photo from August 2017 of a 5 × 5 km area about 7 km southwest of the city center.
- Forest lost since 2001
- 263 haabout 370 football pitches
- Share of its forest
- 2.2%of what there was in 2000
- Cleared for good
- 29 hadeforestation: turned into farms, mines or towns
The worst year was 2004, when about 40 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 | under 1 ha | 7 ha | 7 ha |
| 2002 | 6 ha | 11 ha | 17 ha |
| 2003 | under 1 ha | 16 ha | 16 ha |
| 2004 | under 1 ha | 39 ha | 40 ha |
| 2005 | 1 ha | 24 ha | 25 ha |
| 2006 | 1 ha | 12 ha | 13 ha |
| 2007 | 4 ha | 17 ha | 21 ha |
| 2008 | 3 ha | 4 ha | 7 ha |
| 2009 | 1 ha | 5 ha | 6 ha |
| 2010 | 1 ha | 5 ha | 6 ha |
| 2011 | under 1 ha | 5 ha | 5 ha |
| 2012 | 3 ha | 13 ha | 16 ha |
| 2013 | 2 ha | 1 ha | 3 ha |
| 2014 | under 1 ha | under 1 ha | 2 ha |
| 2015 | under 1 ha | under 1 ha | under 1 ha |
| 2016 | 1 ha | 5 ha | 6 ha |
| 2017 | under 1 ha | 5 ha | 6 ha |
| 2018 | 1 ha | 1 ha | 2 ha |
| 2019 | 1 ha | 8 ha | 9 ha |
| 2020 | under 1 ha | 9 ha | 9 ha |
| 2021 | under 1 ha | 8 ha | 8 ha |
| 2022 | under 1 ha | 16 ha | 16 ha |
| 2023 | under 1 ha | 8 ha | 8 ha |
| 2024 | under 1 ha | 6 ha | 6 ha |
| 2025 | under 1 ha | 10 ha | 10 ha |
What is causing deforestation around Saijō?
- Loggingcan grow back81% · 213 ha
- Towns and roadscleared for good11% · 29 ha
- Storms, floods and other natural causescan grow back2.2% · 6 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
- 12,800 ha
- Forest in 2020
- 12,800 ha
- Overall change
- −1 haless forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Saijō stayed about the same size, at about 12,800 hectares: new forest grew on about 45 hectares, and about 46 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 Saijō
What is the air quality (AQI) in Saijō right now?
The latest reading for Saijō shows an AQI of 28 (Good), measured Nov 12, 00:00 local time by the Asahimachi, Imabari, Ehime, Japan (今治旭今治市) ground monitoring station, 23.5 km away, via OpenAQ. The main pollutant is PM2.5. Air quality is satisfactory for everyone.
Is it safe to exercise outside in Saijō today?
At AQI 28 (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 Saijō been like this week?
Over the last 7 days, the CAMS air-quality model put Saijō's daily AQI at 36 on average, from 25 on Nov 10 to an hourly peak of 68 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 Saijō lost since 2001?
Since 2001, the area within 10 km of Saijō has lost about 263 hectares of forest (about 370 football pitches): 2.2% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 29 hectares (11%) was deforestation: forest cleared for good for farms, mines or towns. Comparing satellite maps from 2000 and 2020, the forest around Saijō stayed about the same size, at about 12,800 hectares: new forest grew on about 45 hectares, and about 46 hectares were lost.
What is the tree count in Saijō?
Saijō has an estimated 20,978 trees across the 12.34 km² of land measured — 6.8% tree cover, 23 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Saijō need?
Saijō needs roughly 71,573 more trees to close a 23-point shortfall against its 30% tree-cover target — about 1,575 t of extra CO₂ absorbed per year once grown.
How are Saijō's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Omachi, via OpenAQ; the 7-day trend is the Open-Meteo / CAMS model's estimate. 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 Omachi; the tree count is an estimate derived from that cover.
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