City report · North Rhine-Westphalia, Germany
Siegen Air quality today
Air quality in Siegen currently reads AQI 62 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Air quality right now
AQI 62
Moderate
- PM2.5, fine particles (µg/m³)
- 14.9
- tree cover
- 57.9%
- trees in this area
- 182K
- more trees needed
- 0
Measured across a 2 km radius around Siegen, Germany (12.57 km²), from a satellite image of Sep 25, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Siegen · AQI 62 (Moderate)
Siegen's tree count comes to 181,898 trees across 12.57 km², already at or above the 30% tree-cover level considered healthy for this area.
Air quality detail
Air quality in Siegen today: AQI 62, Moderate
Main pollutant: PM2.5 · Observed Nov 11, 16:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Olpe1.1, 22.1 km away · median of 5 stations
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
14.9
PM10
1.0
NO₂
9.1
O₃
11.2
SO₂
—
CO
—
Data: OpenAQ · AirGradient, EEA, Olpe, yatil
- 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 Siegen's daily AQI at 62 on average, from 40 on Nov 4 to an hourly peak of 87 on Nov 7.
Where Siegen stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Siegen: Healthy tree cover
57.9% tree cover against a 30% healthy-neighborhood target, across 12.57 km².
Trees in this area
181,898
Target trees
181,898
More trees needed
0
CO₂ if planted / yr
0 kg
Deforestation · 2001–2025
How much forest has Siegen lost?
Since 2001, the area within 10 km of Siegen has lost about 8,720 hectares of forest (about 12,000 football pitches): 40% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 71 hectares (under 1%) 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 south of the city center.
- Forest lost since 2001
- 8,720 haabout 12,000 football pitches
- Share of its forest
- 40%of what there was in 2000
- Cleared for good
- 71 hadeforestation: turned into farms, mines or towns
Forest loss is speeding up: about 875 hectares a year in 2021–2025, up from 363 hectares a year in 2016–2020. The worst year was 2021, when about 3,030 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 | 37 ha | 38 ha |
| 2002 | under 1 ha | 19 ha | 19 ha |
| 2003 | under 1 ha | 34 ha | 34 ha |
| 2004 | 3 ha | 216 ha | 219 ha |
| 2005 | under 1 ha | 40 ha | 40 ha |
| 2006 | under 1 ha | 69 ha | 70 ha |
| 2007 | under 1 ha | 816 ha | 817 ha |
| 2008 | 27 ha | 561 ha | 588 ha |
| 2009 | under 1 ha | 51 ha | 52 ha |
| 2010 | 10 ha | 432 ha | 442 ha |
| 2011 | 2 ha | 33 ha | 35 ha |
| 2012 | 1 ha | 57 ha | 58 ha |
| 2013 | under 1 ha | 41 ha | 41 ha |
| 2014 | 3 ha | 47 ha | 49 ha |
| 2015 | under 1 ha | 26 ha | 27 ha |
| 2016 | under 1 ha | 50 ha | 51 ha |
| 2017 | 2 ha | 53 ha | 56 ha |
| 2018 | under 1 ha | 68 ha | 68 ha |
| 2019 | 2 ha | 440 ha | 442 ha |
| 2020 | 3 ha | 1,200 ha | 1,200 ha |
| 2021 | 7 ha | 3,020 ha | 3,030 ha |
| 2022 | 2 ha | 826 ha | 828 ha |
| 2023 | 3 ha | 403 ha | 406 ha |
| 2024 | 2 ha | 90 ha | 91 ha |
| 2025 | under 1 ha | 22 ha | 22 ha |
What is causing deforestation around Siegen?
- Loggingcan grow back99% · 8,650 ha
Also: towns and roads, 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
- 25,000 ha
- Forest in 2020
- 23,900 ha
- Overall change
- −1,160 haless forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Siegen shrank from about 25,000 hectares to 23,900 hectares, a net loss of about 1,160 hectares (−4.6%). New forest grew on about 160 hectares, but 1,320 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 Siegen
What is the air quality (AQI) in Siegen right now?
The latest reading for Siegen shows an AQI of 62 (Moderate), measured Nov 11, 16:00 local time by 5 ground monitoring stations via OpenAQ (the median of their readings; the nearest is Olpe1.1, 22.1 km away). The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Siegen today?
At AQI 62 (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 Siegen been like this week?
Over the last 7 days, the CAMS air-quality model put Siegen's daily AQI at 62 on average, from 40 on Nov 4 to an hourly peak of 87 on Nov 7. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around Siegen lost since 2001?
Since 2001, the area within 10 km of Siegen has lost about 8,720 hectares of forest (about 12,000 football pitches): 40% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 71 hectares (under 1%) was deforestation: forest cleared for good for farms, mines or towns. Forest loss is speeding up: about 875 hectares a year in 2021–2025, up from 363 hectares a year in 2016–2020. Comparing satellite maps from 2000 and 2020, the forest around Siegen shrank from about 25,000 hectares to 23,900 hectares, a net loss of about 1,160 hectares (−4.6%). New forest grew on about 160 hectares, but 1,320 hectares were lost.
What is the tree count in Siegen?
Siegen has an estimated 181,898 trees across the 12.57 km² measured — 57.9% tree cover, already past the 30% tree-cover target set for this area.
How many more trees does Siegen need?
Siegen has already reached its tree-cover target, so no additional trees are needed to close the gap.
How are Siegen's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Siegen, 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 Siegen; the tree count is an estimate derived from that cover.
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