City report · North Rhine-Westphalia, Germany
Bielefeld Air quality today
Air quality in Bielefeld currently reads AQI 123 (Unhealthy for sensitive groups): Sensitive groups should limit long or intense outdoor activity.
AQI 123
Air quality right now
Unhealthy for sensitive groups
- PM2.5, fine particles (µg/m³)
- 44.5
- tree cover
- 40.8%
- trees in this area
- 128K
- more trees needed
- 0
Measured across a 2 km radius around Mitte, Bielefeld, Germany (12.57 km²), from a satellite image of Sep 25, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Bielefeld · AQI 123 (Unhealthy for sensitive groups)
Bielefeld's tree count comes to 128,049 trees across 12.56 km² of land, already at or above the 35% tree-cover level considered healthy for this area.
Air quality detail
Air quality in Bielefeld today: AQI 123, Unhealthy for sensitive groups
Main pollutant: PM2.5 · Observed Nov 11, 18:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Hücker-Aschen, 14.7 km away · median of 3 stations
Health signal
Sensitive groups should limit long or intense outdoor activity.
PM2.5
44.5
PM10
16.2
NO₂
26.9
O₃
—
SO₂
—
CO
—
Data: OpenAQ · AirGradient, EEA, 4WTM
- Outdoor exercise
- Children, older adults and people with asthma or heart disease should cut down long or hard exercise
- Windows
- Close them to keep the outside air out
- Mask
- Sensitive groups: an N95 outdoors
- Air purifier
- Run one, especially in bedrooms
Over the last 7 days, the CAMS air-quality model put Bielefeld's daily AQI at 64 on average, from 41 on Nov 4 to an hourly peak of 86 on Nov 10.
Where Bielefeld stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Bielefeld: Healthy tree cover
40.8% tree cover against a 35% healthy-neighborhood target, across 12.56 km² of land.
Trees in this area
128,049
Target trees
128,049
More trees needed
0
CO₂ if planted / yr
0 kg
Deforestation · 2001–2025
How much forest has Bielefeld lost?
Since 2001, the area within 10 km of Bielefeld has lost about 750 hectares of forest (about 1,100 football pitches): 8.9% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 82 hectares (11%) 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 southeast of the city center.
- Forest lost since 2001
- 750 haabout 1,100 football pitches
- Share of its forest
- 8.9%of what there was in 2000
- Cleared for good
- 82 hadeforestation: turned into farms, mines or towns
Forest loss has stayed about the same: about 57 hectares a year in 2021–2025, against 57 hectares a year in 2016–2020. The worst year was 2021, when about 213 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 | 1 ha | 4 ha | 5 ha |
| 2002 | under 1 ha | under 1 ha | 1 ha |
| 2003 | under 1 ha | under 1 ha | under 1 ha |
| 2004 | 5 ha | 6 ha | 11 ha |
| 2005 | 3 ha | 3 ha | 6 ha |
| 2006 | 3 ha | 5 ha | 8 ha |
| 2007 | 3 ha | 14 ha | 17 ha |
| 2008 | 17 ha | 14 ha | 31 ha |
| 2009 | 11 ha | 5 ha | 16 ha |
| 2010 | 13 ha | 37 ha | 50 ha |
| 2011 | under 1 ha | 2 ha | 3 ha |
| 2012 | 3 ha | 11 ha | 13 ha |
| 2013 | 2 ha | 6 ha | 8 ha |
| 2014 | 2 ha | 9 ha | 11 ha |
| 2015 | under 1 ha | under 1 ha | 1 ha |
| 2016 | 1 ha | 2 ha | 3 ha |
| 2017 | 2 ha | 14 ha | 17 ha |
| 2018 | 2 ha | 17 ha | 19 ha |
| 2019 | 2 ha | 53 ha | 55 ha |
| 2020 | 2 ha | 187 ha | 189 ha |
| 2021 | 4 ha | 209 ha | 213 ha |
| 2022 | 1 ha | 29 ha | 30 ha |
| 2023 | 2 ha | 36 ha | 38 ha |
| 2024 | under 1 ha | 1 ha | 2 ha |
| 2025 | under 1 ha | 2 ha | 3 ha |
What is causing deforestation around Bielefeld?
- Loggingcan grow back86% · 645 ha
- Towns and roadscleared for good11% · 82 ha
- Unknown causescause unknown3% · 22 ha
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
- 9,330 ha
- Forest in 2020
- 9,380 ha
- Overall change
- +46 hamore forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Bielefeld stayed about the same size, at about 9,380 hectares: new forest grew on about 358 hectares, and about 312 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 Bielefeld
What is the air quality (AQI) in Bielefeld right now?
The latest reading for Bielefeld shows an AQI of 123 (Unhealthy for sensitive groups), measured Nov 11, 18:00 local time by 3 ground monitoring stations via OpenAQ (the median of their readings; the nearest is Hücker-Aschen, 14.7 km away). The main pollutant is PM2.5. Sensitive groups should limit long or intense outdoor activity.
Is it safe to exercise outside in Bielefeld today?
At AQI 123 (Unhealthy for sensitive groups): children, older adults and people with asthma or heart disease should cut down long or hard exercise. Windows: close them to keep the outside air out. Masks: sensitive groups: an N95 outdoors. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Bielefeld been like this week?
Over the last 7 days, the CAMS air-quality model put Bielefeld's daily AQI at 64 on average, from 41 on Nov 4 to an hourly peak of 86 on Nov 10. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around Bielefeld lost since 2001?
Since 2001, the area within 10 km of Bielefeld has lost about 750 hectares of forest (about 1,100 football pitches): 8.9% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 82 hectares (11%) was deforestation: forest cleared for good for farms, mines or towns. Forest loss has stayed about the same: about 57 hectares a year in 2021–2025, against 57 hectares a year in 2016–2020. Comparing satellite maps from 2000 and 2020, the forest around Bielefeld stayed about the same size, at about 9,380 hectares: new forest grew on about 358 hectares, and about 312 hectares were lost.
What is the tree count in Bielefeld?
Bielefeld has an estimated 128,049 trees across the 12.56 km² of land measured — 40.8% tree cover, already past the 35% tree-cover target set for this area.
How many more trees does Bielefeld need?
Bielefeld has already reached its tree-cover target, so no additional trees are needed to close the gap.
How are Bielefeld's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Mitte, 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 Mitte; the tree count is an estimate derived from that cover.
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