City report · Gyeonggi-do, South Korea
Osan Air quality today
Air quality in Osan currently reads AQI 81 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
AQI 81
Air quality right now
Moderate
- PM2.5, fine particles (µg/m³)
- 25.0
- tree cover
- 20.3%
- trees in this area
- 63.8K
- more trees needed
- 30.5K
Measured across a 2 km radius around Seonghosaessak 38beon-gil, Osan-si, Gyeonggi-do, South Korea (12.57 km²), from a satellite image of Sep 23, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Osan · AQI 81 (Moderate)
Osan's tree count comes to 63,774 trees across 12.57 km², 10 points below the 30% tree-cover level considered healthy for this area, so roughly 30,473 more trees would close the gap.
Air quality detail
Air quality in Osan today: AQI 81, Moderate
Main pollutant: PM2.5 · Observed Nov 12, 01:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · 금암로(신장동), 2.7 km away · median of 6 stations
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
25.0
PM10
45.0
NO₂
65.3
O₃
4.9
SO₂
7.1
CO
584.3
Data: OpenAQ · Korea Air Ministry of Environment, Korea Environment Corporation · AirKorea
- 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 Osan's daily AQI at 76 on average, from 56 on Nov 6 to an hourly peak of 115 on Nov 10.
Where Osan stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Osan: Below target
20.3% tree cover against a 30% healthy-neighborhood target, across 12.57 km².
Trees in this area
63,774
Target trees
94,247
More trees needed
30,473
CO₂ if planted / yr
670.4 t
Deforestation · 2001–2025
How much forest has Osan lost?
Since 2001, the area within 10 km of Osan has lost about 1,340 hectares of forest (about 1,900 football pitches): 24% of the forest it had in 2000. Most of it (81%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from August 2017 of a 5 × 5 km area about 6 km east of the city center.
- Forest lost since 2001
- 1,340 haabout 1,900 football pitches
- Share of its forest
- 24%of what there was in 2000
- Cleared for good
- 1,090 hadeforestation: turned into farms, mines or towns
Forest loss is slowing down: about 26 hectares a year in 2021–2025, down from 55 hectares a year in 2016–2020. The worst year was 2011, when about 153 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 | 35 ha | 5 ha | 40 ha |
| 2002 | 13 ha | 1 ha | 15 ha |
| 2003 | 25 ha | 6 ha | 30 ha |
| 2004 | 111 ha | 5 ha | 116 ha |
| 2005 | 34 ha | 3 ha | 37 ha |
| 2006 | 56 ha | 4 ha | 60 ha |
| 2007 | 34 ha | 4 ha | 38 ha |
| 2008 | 47 ha | 10 ha | 57 ha |
| 2009 | 20 ha | 10 ha | 30 ha |
| 2010 | 38 ha | 17 ha | 55 ha |
| 2011 | 137 ha | 16 ha | 153 ha |
| 2012 | 120 ha | 4 ha | 124 ha |
| 2013 | 77 ha | 4 ha | 81 ha |
| 2014 | 53 ha | 4 ha | 57 ha |
| 2015 | 39 ha | 7 ha | 47 ha |
| 2016 | 62 ha | 6 ha | 68 ha |
| 2017 | 63 ha | 19 ha | 82 ha |
| 2018 | 33 ha | 29 ha | 62 ha |
| 2019 | 22 ha | 6 ha | 28 ha |
| 2020 | 19 ha | 16 ha | 35 ha |
| 2021 | 20 ha | 26 ha | 46 ha |
| 2022 | 7 ha | 4 ha | 11 ha |
| 2023 | 7 ha | 31 ha | 38 ha |
| 2024 | 3 ha | 12 ha | 15 ha |
| 2025 | 12 ha | 10 ha | 22 ha |
What is causing deforestation around Osan?
- Towns and roadscleared for good79% · 1,060 ha
- Loggingcan grow back19% · 256 ha
- Mining and energycleared for good1.7% · 23 ha
Also: farms, pasture and plantations, 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
- 7,280 ha
- Forest in 2020
- 6,290 ha
- Overall change
- −991 haless forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Osan shrank from about 7,280 hectares to 6,290 hectares, a net loss of about 991 hectares (−14%). New forest grew on about 274 hectares, but 1,260 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
In the same region
Measured cities near Osan
Same 2 km radius, same index — so they compare directly.
- Suwon16.4 km
South Korea
- Tree cover
- 20%
- Air quality
- 88
- Pyeongtaek17.6 km
South Korea
- Tree cover
- 10%
- Air quality
- 126
- Hwaseong-si23.3 km
South Korea
- Tree cover
- 45%
- Air quality
- 82
- Ansan-si29.1 km
South Korea
- Tree cover
- 30%
- Air quality
- 92
- Anyang-si29.6 km
South Korea
- Tree cover
- 40%
- Air quality
- 84
- Seongnam-si32.4 km
South Korea
- Tree cover
- 32%
- Air quality
- 85
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Frequently asked
Questions about Osan
What is the air quality (AQI) in Osan right now?
The latest reading for Osan shows an AQI of 81 (Moderate), measured Nov 12, 01:00 local time by 6 ground monitoring stations via OpenAQ (the median of their readings; the nearest is 금암로(신장동), 2.7 km away). The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Osan today?
At AQI 81 (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 Osan been like this week?
Over the last 7 days, the CAMS air-quality model put Osan's daily AQI at 76 on average, from 56 on Nov 6 to an hourly peak of 115 on Nov 10. On 1 of those days the average was above 100, unhealthy for sensitive groups.
How much forest has the area around Osan lost since 2001?
Since 2001, the area within 10 km of Osan has lost about 1,340 hectares of forest (about 1,900 football pitches): 24% of the forest it had in 2000. Most of it (81%) was deforestation, forest cleared for good, mainly for towns and roads. Forest loss is slowing down: about 26 hectares a year in 2021–2025, down from 55 hectares a year in 2016–2020. Comparing satellite maps from 2000 and 2020, the forest around Osan shrank from about 7,280 hectares to 6,290 hectares, a net loss of about 991 hectares (−14%). New forest grew on about 274 hectares, but 1,260 hectares were lost.
What is the tree count in Osan?
Osan has an estimated 63,774 trees across the 12.57 km² measured — 20.3% tree cover, 10 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Osan need?
Osan needs roughly 30,473 more trees to close a 10-point shortfall against its 30% tree-cover target — about 670.4 t of extra CO₂ absorbed per year once grown.
How are Osan's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Seonghosaessak 38beon-gil, 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 Seonghosaessak 38beon-gil; the tree count is an estimate derived from that cover.
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