City report · Shiga, Japan
Ōtsu Air quality today
Air quality in Ōtsu currently reads AQI 51 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
AQI 51
Air quality right now
Moderate
- PM2.5, fine particles (µg/m³)
- 9.1
- tree cover
- 45.5%
- trees in this area
- 123K
- more trees needed
- 0
Measured across a 2 km radius around 1 Chome-4 Asahigaoka, Otsu, Shiga 520-0052, Japan (12.57 km²), from a satellite image of Jul 23, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Ōtsu · AQI 51 (Moderate)
Ōtsu's tree count comes to 122,931 trees across 10.81 km² of land, already at or above the 30% tree-cover level considered healthy for this area.
Air quality detail
Air quality in Ōtsu today: AQI 51, Moderate
Main pollutant: PM2.5 · Observed Nov 11, 23:00 local time via World Air Quality Index Project ground stations, US EPA index. Values in µg/m³.
Ground station · Terada, Joyo, Kyoto Prefecture, Japan (城陽城陽市), 17.8 km away
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
9.1
PM10
9.7
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), Kyoto Prefecture EPA (大気環境の保全対策／京都府ホームページ)
- Outdoor exercise
- Fine for most people; unusually sensitive people should take long or hard exercise easier
- Windows
- Fine to open; close them if you are sensitive to pollution
- Mask
- Not needed for most people
- Air purifier
- Worth running if you are sensitive
Over the last 7 days, the CAMS air-quality model put Ōtsu's daily AQI at 37 on average, from 18 on Nov 11 to an hourly peak of 71 on Nov 5.
Where Ōtsu stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Ōtsu: Healthy tree cover
45.5% tree cover against a 30% healthy-neighborhood target, across 10.81 km² of land.
Trees in this area
122,931
Target trees
122,931
More trees needed
0
CO₂ if planted / yr
0 kg
Deforestation · 2001–2025
How much forest has Ōtsu lost?
Since 2001, the area within 10 km of Ōtsu has lost about 204 hectares of forest (about 290 football pitches): 1.6% of the forest it had in 2000. Most of it (64%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from August 2017 of a 5 × 5 km area in the city center.
- Forest lost since 2001
- 204 haabout 290 football pitches
- Share of its forest
- 1.6%of what there was in 2000
- Cleared for good
- 130 hadeforestation: turned into farms, mines or towns
The worst year was 2019, when about 16 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 | 3 ha | 2 ha | 6 ha |
| 2002 | 3 ha | 4 ha | 7 ha |
| 2003 | 5 ha | under 1 ha | 6 ha |
| 2004 | 6 ha | 4 ha | 10 ha |
| 2005 | 8 ha | 3 ha | 12 ha |
| 2006 | 9 ha | 7 ha | 15 ha |
| 2007 | 11 ha | 4 ha | 15 ha |
| 2008 | 6 ha | 4 ha | 11 ha |
| 2009 | 5 ha | 5 ha | 10 ha |
| 2010 | 9 ha | 3 ha | 12 ha |
| 2011 | 7 ha | 3 ha | 9 ha |
| 2012 | 6 ha | 4 ha | 10 ha |
| 2013 | 2 ha | under 1 ha | 3 ha |
| 2014 | 2 ha | under 1 ha | 2 ha |
| 2015 | 3 ha | 2 ha | 5 ha |
| 2016 | 13 ha | 2 ha | 15 ha |
| 2017 | 2 ha | under 1 ha | 2 ha |
| 2018 | 3 ha | 7 ha | 10 ha |
| 2019 | 8 ha | 8 ha | 16 ha |
| 2020 | 10 ha | 4 ha | 14 ha |
| 2021 | 4 ha | under 1 ha | 4 ha |
| 2022 | under 1 ha | under 1 ha | 1 ha |
| 2023 | 1 ha | 3 ha | 4 ha |
| 2024 | 4 ha | 2 ha | 7 ha |
| 2025 | under 1 ha | 1 ha | 1 ha |
What is causing deforestation around Ōtsu?
- Towns and roadscleared for good57% · 116 ha
- Loggingcan grow back29% · 59 ha
- Mining and energycleared for good6.9% · 14 ha
Also: storms, floods and other natural causes, 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
- 13,300 ha
- Forest in 2020
- 13,200 ha
- Overall change
- −90 haless forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Ōtsu stayed about the same size, at about 13,200 hectares: new forest grew on about 59 hectares, and about 148 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 Ōtsu
What is the air quality (AQI) in Ōtsu right now?
The latest reading for Ōtsu shows an AQI of 51 (Moderate), measured Nov 11, 23:00 local time by the Terada, Joyo, Kyoto Prefecture, Japan (城陽城陽市) ground monitoring station, 17.8 km away, via OpenAQ. The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Ōtsu today?
At AQI 51 (Moderate): fine for most people; unusually sensitive people should take long or hard exercise easier. Windows: fine to open; close them if you are sensitive to pollution. Masks: not needed for most people. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Ōtsu been like this week?
Over the last 7 days, the CAMS air-quality model put Ōtsu's daily AQI at 37 on average, from 18 on Nov 11 to an hourly peak of 71 on Nov 5. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around Ōtsu lost since 2001?
Since 2001, the area within 10 km of Ōtsu has lost about 204 hectares of forest (about 290 football pitches): 1.6% of the forest it had in 2000. Most of it (64%) was deforestation, forest cleared for good, mainly for towns and roads. Comparing satellite maps from 2000 and 2020, the forest around Ōtsu stayed about the same size, at about 13,200 hectares: new forest grew on about 59 hectares, and about 148 hectares were lost.
What is the tree count in Ōtsu?
Ōtsu has an estimated 122,931 trees across the 10.81 km² of land measured — 45.5% tree cover, already past the 30% tree-cover target set for this area.
How many more trees does Ōtsu need?
Ōtsu has already reached its tree-cover target, so no additional trees are needed to close the gap.
How are Ōtsu's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near 1 Chome-4 Asahigaoka, 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 1 Chome-4 Asahigaoka; the tree count is an estimate derived from that cover.
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