City report · Gyeonggi-do, South Korea
Ansan-si Air quality today
Air quality in Ansan-si currently reads AQI 92 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Air quality right now
AQI 92
Moderate
- PM2.5, fine particles (µg/m³)
- 31.0
- tree cover
- 30.2%
- trees in this area
- 94.6K
- more trees needed
- 0
Measured across a 2 km radius around South Korea, 경기도 안산시 단원구 고잔동 (12.57 km²), from a satellite image of Sep 23, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Ansan-si · AQI 92 (Moderate)
Ansan-si's tree count comes to 94,591 trees across 12.53 km² of land, already at or above the 30% tree-cover level considered healthy for this area.
Air quality detail
Air quality in Ansan-si today: AQI 92, Moderate
Main pollutant: PM2.5 · Observed Nov 12, 00:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · 고잔동, 800 m away · median of 11 stations
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
31.0
PM10
44.0
NO₂
86.9
O₃
3.3
SO₂
8.1
CO
767.5
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 Ansan-si's daily AQI at 72 on average, from 51 on Nov 6 to an hourly peak of 113 on Nov 11.
Where Ansan-si stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Ansan-si: Healthy tree cover
30.2% tree cover against a 30% healthy-neighborhood target, across 12.53 km² of land.
Trees in this area
94,591
Target trees
94,591
More trees needed
0
CO₂ if planted / yr
0 kg
Deforestation · 2001–2025
How much forest has Ansan-si lost?
Since 2001, the area within 10 km of Ansan-si has lost about 134 hectares of forest (about 190 football pitches): 2.8% of the forest it had in 2000. Most of it (60%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
- Forest lost since 2001
- 134 haabout 190 football pitches
- Share of its forest
- 2.8%of what there was in 2000
- Cleared for good
- 80 hadeforestation: turned into farms, mines or towns
The worst year was 2013, when about 19 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 | under 1 ha | 1 ha |
| 2002 | 1 ha | under 1 ha | 2 ha |
| 2003 | 2 ha | under 1 ha | 2 ha |
| 2004 | under 1 ha | under 1 ha | 1 ha |
| 2005 | 4 ha | 2 ha | 5 ha |
| 2006 | 5 ha | 3 ha | 7 ha |
| 2007 | 4 ha | 3 ha | 7 ha |
| 2008 | 4 ha | 1 ha | 5 ha |
| 2009 | 2 ha | 4 ha | 5 ha |
| 2010 | 2 ha | 2 ha | 4 ha |
| 2011 | 3 ha | 3 ha | 7 ha |
| 2012 | 6 ha | 2 ha | 8 ha |
| 2013 | 16 ha | 2 ha | 19 ha |
| 2014 | 4 ha | under 1 ha | 5 ha |
| 2015 | 4 ha | 3 ha | 6 ha |
| 2016 | 2 ha | 3 ha | 5 ha |
| 2017 | 4 ha | 2 ha | 6 ha |
| 2018 | under 1 ha | 1 ha | 2 ha |
| 2019 | 3 ha | under 1 ha | 3 ha |
| 2020 | 4 ha | under 1 ha | 5 ha |
| 2021 | under 1 ha | 3 ha | 4 ha |
| 2022 | 1 ha | 2 ha | 4 ha |
| 2023 | 4 ha | 10 ha | 14 ha |
| 2024 | under 1 ha | under 1 ha | under 1 ha |
| 2025 | 2 ha | 4 ha | 6 ha |
What is causing deforestation around Ansan-si?
- Towns and roadscleared for good60% · 80 ha
- Loggingcan grow back33% · 44 ha
- Unknown causescause unknown6.1% · 8 ha
Also: wildfires, storms, floods and other natural causes, mining and energy.
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
- 7,350 ha
- Forest in 2020
- 7,460 ha
- Overall change
- +110 hamore forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Ansan-si stayed about the same size, at about 7,460 hectares: new forest grew on about 280 hectares, and about 170 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 Ansan-si
Same 2 km radius, same index — so they compare directly.
- Anyang-si12.0 km
South Korea
- Tree cover
- 40%
- Air quality
- 84
- Hwaseong-si13.0 km
South Korea
- Tree cover
- 45%
- Air quality
- 96
- Suwon16.9 km
South Korea
- Tree cover
- 20%
- Air quality
- 82
- Incheon18.0 km
South Korea
- Tree cover
- 12%
- Air quality
- 89
- Bucheon-si19.8 km
South Korea
- Tree cover
- 27%
- Air quality
- 96
- Osan29.1 km
South Korea
- Tree cover
- 20%
- Air quality
- 90
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Frequently asked
Questions about Ansan-si
What is the air quality (AQI) in Ansan-si right now?
The latest reading for Ansan-si shows an AQI of 92 (Moderate), measured Nov 12, 00:00 local time by 11 ground monitoring stations via OpenAQ (the median of their readings; the nearest is 고잔동, 800 m away). The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Ansan-si today?
At AQI 92 (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 Ansan-si been like this week?
Over the last 7 days, the CAMS air-quality model put Ansan-si's daily AQI at 72 on average, from 51 on Nov 6 to an hourly peak of 113 on Nov 11. On 1 of those days the average was above 100, unhealthy for sensitive groups.
How much forest has the area around Ansan-si lost since 2001?
Since 2001, the area within 10 km of Ansan-si has lost about 134 hectares of forest (about 190 football pitches): 2.8% of the forest it had in 2000. Most of it (60%) was deforestation, forest cleared for good, mainly for towns and roads. Comparing satellite maps from 2000 and 2020, the forest around Ansan-si stayed about the same size, at about 7,460 hectares: new forest grew on about 280 hectares, and about 170 hectares were lost.
What is the tree count in Ansan-si?
Ansan-si has an estimated 94,591 trees across the 12.53 km² of land measured — 30.2% tree cover, already past the 30% tree-cover target set for this area.
How many more trees does Ansan-si need?
Ansan-si has already reached its tree-cover target, so no additional trees are needed to close the gap.
How are Ansan-si's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near South Korea, 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 South Korea; the tree count is an estimate derived from that cover.
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