City report · England, United Kingdom
Slough Air quality today
Air quality in Slough currently reads AQI 57 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
AQI 57
Air quality right now
Moderate
- PM2.5, fine particles (µg/m³)
- 12.4
- tree cover
- 21.3%
- trees in this area
- 66.9K
- more trees needed
- 27.3K
Measured across a 1.2 mi (2 km) radius around Slough, UK (4.9 sq mi), from a satellite image of Aug 25, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Slough · AQI 57 (Moderate)
Slough's tree count comes to 66,916 trees across 4.9 sq mi (12.57 km²), 9 points below the 30% tree-cover level considered healthy for this area, so roughly 27,332 more trees would close the gap.
Air quality detail
Air quality in Slough today: AQI 57, Moderate
Main pollutant: PM2.5 · Observed Nov 11, 17:00 local time via OpenAQ and World Air Quality Index Project ground stations, US EPA index. Values in µg/m³.
Ground station · London Harlington, United Kingdom, 6.8 mi (10.9 km) away · median of 6 stations
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
12.4
PM10
20.5
NO₂
38.3
O₃
—
SO₂
—
CO
—
Data: OpenAQ · DEFRA, London Air Quality Network, World Air Quality Index Project, UK-AIR, air quality information resource - Defra, UK, London Air Quality Network - Environmental Research Group, King's College London
- 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 Slough's daily AQI at 71 on average, from 37 on Nov 4 to an hourly peak of 110 on Nov 6.
This is the US EPA AQI. How it differs from the UK's Daily Air Quality Index
Where Slough stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Slough: Below target
21.3% tree cover against a 30% healthy-neighborhood target, across 4.9 sq mi (12.57 km²).
Trees in this area
66,916
Target trees
94,248
More trees needed
27,332
CO₂ if planted / yr
601.3 t
Deforestation · 2001–2025
How much forest has Slough lost?
Since 2001, the area within 10 km of Slough has lost about 143 hectares of forest (about 200 football pitches): 2.2% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 22 hectares (15%) was deforestation: forest cleared for good for farms, mines or towns.
2018: satellite photo from August 2018 of a 5 × 5 km area in the city center.
- Forest lost since 2001
- 143 haabout 200 football pitches
- Share of its forest
- 2.2%of what there was in 2000
- Cleared for good
- 22 hadeforestation: turned into farms, mines or towns
The worst year was 2008, when about 28 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 | 3 ha | 3 ha |
| 2002 | under 1 ha | under 1 ha | 1 ha |
| 2003 | under 1 ha | under 1 ha | under 1 ha |
| 2004 | under 1 ha | 3 ha | 3 ha |
| 2005 | under 1 ha | under 1 ha | under 1 ha |
| 2006 | under 1 ha | 17 ha | 18 ha |
| 2007 | 5 ha | 7 ha | 11 ha |
| 2008 | 6 ha | 22 ha | 28 ha |
| 2009 | under 1 ha | under 1 ha | under 1 ha |
| 2010 | 1 ha | 7 ha | 8 ha |
| 2011 | under 1 ha | 10 ha | 10 ha |
| 2012 | under 1 ha | under 1 ha | under 1 ha |
| 2013 | under 1 ha | 5 ha | 5 ha |
| 2014 | 1 ha | 10 ha | 11 ha |
| 2015 | under 1 ha | under 1 ha | 1 ha |
| 2016 | 2 ha | 4 ha | 6 ha |
| 2017 | under 1 ha | 10 ha | 10 ha |
| 2018 | under 1 ha | 2 ha | 2 ha |
| 2019 | 3 ha | 3 ha | 6 ha |
| 2020 | under 1 ha | under 1 ha | 1 ha |
| 2021 | under 1 ha | 5 ha | 5 ha |
| 2022 | under 1 ha | 2 ha | 2 ha |
| 2023 | under 1 ha | 1 ha | 1 ha |
| 2024 | under 1 ha | 3 ha | 3 ha |
| 2025 | under 1 ha | 7 ha | 7 ha |
What is causing deforestation around Slough?
- Loggingcan grow back78% · 112 ha
- Towns and roadscleared for good15% · 21 ha
- Unknown causescause unknown6.8% · 10 ha
Also: farms, pasture and plantations.
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
- 11,500 ha
- Forest in 2020
- 12,000 ha
- Overall change
- +510 hamore forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Slough grew from about 11,500 hectares to 12,000 hectares, a net gain of about 510 hectares (+4.4%). New forest grew on about 613 hectares, while 102 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 Slough
Same 2 km radius, same index — so they compare directly.
- High Wycombe17.0 km
United Kingdom
- Tree cover
- 41%
- Air quality
- 81
- Harrow19.8 km
United Kingdom
- Tree cover
- 29%
- Air quality
- 52
- Watford21.3 km
United Kingdom
- Tree cover
- 30%
- Air quality
- 56
- Woking21.3 km
United Kingdom
- Tree cover
- 54%
- Air quality
- 126
- Reading26.7 km
United Kingdom
- Tree cover
- 28%
- Air quality
- 81
- London32.4 km
United Kingdom
- Tree cover
- 18%
- Air quality
- 56
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Frequently asked
Questions about Slough
What is the air quality (AQI) in Slough right now?
The latest reading for Slough shows an AQI of 57 (Moderate), measured Nov 11, 17:00 local time by 6 ground monitoring stations via OpenAQ (the median of their readings; the nearest is London Harlington, United Kingdom, 6.8 mi (10.9 km) away). The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Slough today?
At AQI 57 (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 Slough been like this week?
Over the last 7 days, the CAMS air-quality model put Slough's daily AQI at 71 on average, from 37 on Nov 4 to an hourly peak of 110 on Nov 6. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
Is Slough's AQI the same as the UK's Daily Air Quality Index?
No. Airleaf shows the US EPA Air Quality Index (AQI), the scale used by IQAir and most air-quality apps. The UK's Daily Air Quality Index (DAQI), published by Defra, runs from 1 to 10: 1–3 low, 4–6 moderate, 7–9 high and 10 very high. It is a different scale altogether, so a US AQI figure can't be read on it directly; both, though, are built from the same main pollutants, with fine particles (PM2.5) usually the one that decides the reading.
How much forest has the area around Slough lost since 2001?
Since 2001, the area within 10 km of Slough has lost about 143 hectares of forest (about 200 football pitches): 2.2% of the forest it had in 2000. Most of it was lost to logging, so much of it can grow back. About 22 hectares (15%) was deforestation: forest cleared for good for farms, mines or towns. Comparing satellite maps from 2000 and 2020, the forest around Slough grew from about 11,500 hectares to 12,000 hectares, a net gain of about 510 hectares (+4.4%). New forest grew on about 613 hectares, while 102 hectares were lost.
What is the tree count in Slough?
Slough has an estimated 66,916 trees across the 4.9 sq mi (12.57 km²) measured — 21.3% tree cover, 9 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Slough need?
Slough needs roughly 27,332 more trees to close a 9-point shortfall against its 30% tree-cover target — about 601.3 t of extra CO₂ absorbed per year once grown.
How are Slough's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Slough, 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 1.2 mi (2 km) radius around Slough; the tree count is an estimate derived from that cover.
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