City report · South Korea
Ulsan Air quality today
Air quality in Ulsan currently reads AQI 70 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
AQI 70
Air quality right now
Moderate
- PM2.5, fine particles (µg/m³)
- 19.5
- tree cover
- 17.0%
- trees in this area
- 50.8K
- more trees needed
- 38.9K
Measured across a 2 km radius around Dotjil-ro 92beon-gil, Nam-gu, Ulsan, South Korea (12.57 km²), from a satellite image of Sep 12, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Ulsan · AQI 70 (Moderate)
Ulsan's tree count comes to 50,844 trees across 11.97 km² of land, 13 points below the 30% tree-cover level considered healthy for this area, so roughly 38,880 more trees would close the gap.
Air quality detail
Air quality in Ulsan today: AQI 70, Moderate
Main pollutant: PM2.5 · Observed Nov 12, 02:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · 신정로, 1.5 km away · median of 17 stations
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
19.5
PM10
30.0
NO₂
34.2
O₃
32.0
SO₂
5.8
CO
527.0
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 Ulsan's daily AQI at 53 on average, from 46 on Nov 6 to an hourly peak of 79 on Nov 11.
Where Ulsan stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Ulsan: Critically low
17.0% tree cover against a 30% healthy-neighborhood target, across 11.97 km² of land.
Trees in this area
50,844
Target trees
89,724
More trees needed
38,880
CO₂ if planted / yr
855.4 t
Deforestation · 2001–2025
How much forest has Ulsan lost?
Since 2001, the area within 10 km of Ulsan has lost about 1,060 hectares of forest (about 1,500 football pitches): 8.7% of the forest it had in 2000. Most of it (57%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from September 2017 of a 5 × 5 km area about 7 km southwest of the city center.
- Forest lost since 2001
- 1,060 haabout 1,500 football pitches
- Share of its forest
- 8.7%of what there was in 2000
- Cleared for good
- 609 hadeforestation: turned into farms, mines or towns
Forest loss is speeding up: about 60 hectares a year in 2021–2025, up from 44 hectares a year in 2016–2020. The worst year was 2021, when about 200 hectares of forest were lost.
Ulsan's full deforestation reportHectares of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 6 ha | 5 ha | 11 ha |
| 2002 | 12 ha | 3 ha | 15 ha |
| 2003 | 26 ha | under 1 ha | 26 ha |
| 2004 | 36 ha | 21 ha | 58 ha |
| 2005 | 9 ha | 3 ha | 12 ha |
| 2006 | 16 ha | 3 ha | 20 ha |
| 2007 | 34 ha | under 1 ha | 35 ha |
| 2008 | 47 ha | 1 ha | 48 ha |
| 2009 | 41 ha | 4 ha | 45 ha |
| 2010 | 57 ha | under 1 ha | 58 ha |
| 2011 | 8 ha | under 1 ha | 8 ha |
| 2012 | 45 ha | 2 ha | 47 ha |
| 2013 | 20 ha | 15 ha | 36 ha |
| 2014 | 33 ha | 4 ha | 36 ha |
| 2015 | 76 ha | 11 ha | 87 ha |
| 2016 | 39 ha | 16 ha | 54 ha |
| 2017 | 17 ha | 4 ha | 21 ha |
| 2018 | 10 ha | 38 ha | 48 ha |
| 2019 | 11 ha | 7 ha | 18 ha |
| 2020 | 9 ha | 70 ha | 79 ha |
| 2021 | 13 ha | 187 ha | 200 ha |
| 2022 | 2 ha | 39 ha | 41 ha |
| 2023 | 33 ha | 17 ha | 50 ha |
| 2024 | under 1 ha | under 1 ha | 1 ha |
| 2025 | 8 ha | under 1 ha | 9 ha |
What is causing deforestation around Ulsan?
- Towns and roadscleared for good56% · 598 ha
- Loggingcan grow back41% · 439 ha
- Mining and energycleared for good1% · 11 ha
Also: wildfires, 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
- 14,000 ha
- Forest in 2020
- 13,400 ha
- Overall change
- −526 haless forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Ulsan shrank from about 14,000 hectares to 13,400 hectares, a net loss of about 526 hectares (−3.8%). New forest grew on about 323 hectares, but 849 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 Ulsan
What is the air quality (AQI) in Ulsan right now?
The latest reading for Ulsan shows an AQI of 70 (Moderate), measured Nov 12, 02:00 local time by 17 ground monitoring stations via OpenAQ (the median of their readings; the nearest is 신정로, 1.5 km away). The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Ulsan today?
At AQI 70 (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 Ulsan been like this week?
Over the last 7 days, the CAMS air-quality model put Ulsan's daily AQI at 53 on average, from 46 on Nov 6 to an hourly peak of 79 on Nov 11. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around Ulsan lost since 2001?
Since 2001, the area within 10 km of Ulsan has lost about 1,060 hectares of forest (about 1,500 football pitches): 8.7% of the forest it had in 2000. Most of it (57%) was deforestation, forest cleared for good, mainly for towns and roads. Forest loss is speeding up: about 60 hectares a year in 2021–2025, up from 44 hectares a year in 2016–2020. Comparing satellite maps from 2000 and 2020, the forest around Ulsan shrank from about 14,000 hectares to 13,400 hectares, a net loss of about 526 hectares (−3.8%). New forest grew on about 323 hectares, but 849 hectares were lost.
What is the tree count in Ulsan?
Ulsan has an estimated 50,844 trees across the 11.97 km² of land measured — 17.0% tree cover, 13 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Ulsan need?
Ulsan needs roughly 38,880 more trees to close a 13-point shortfall against its 30% tree-cover target — about 855.4 t of extra CO₂ absorbed per year once grown.
How are Ulsan's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Dotjil-ro 92beon-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 Dotjil-ro 92beon-gil; the tree count is an estimate derived from that cover.
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