City report · California, United States
Fremont Air quality today
Air quality in Fremont currently reads AQI 29 (Good): Air quality is satisfactory for everyone.
Air quality right now
AQI 29
Good
- PM2.5, fine particles (µg/m³)
- 5.2
- tree cover
- 15.4%
- trees in this area
- 48.2K
- more trees needed
- 45.7K
Measured across a 1.2 mi (2 km) radius around Sundale, Fremont, CA 94538, USA (4.9 sq mi), from a satellite image of Sep 12, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Fremont · AQI 29 (Good)
Fremont's tree count comes to 48,187 trees across 4.8 sq mi (12.52 km²) of land, 15 points below the 30% tree-cover level considered healthy for this area, so roughly 45,684 more trees would close the gap.
Air quality detail
Air quality in Fremont today: AQI 29, Good
Main pollutant: PM2.5 · Observed Nov 11, 07:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Irvington, Fremont (kcafremo271), 1.2 mi (1.9 km) away · median of 4 stations
Health signal
Air quality is satisfactory for everyone.
PM2.5
5.2
PM10
—
NO₂
—
O₃
—
SO₂
—
CO
—
Data: OpenAQ · AirGradient, John Link, zwoopzwoop, LCF, Guardian
- Outdoor exercise
- A good day to be active outside
- Windows
- Open them to air the house
- Mask
- Not needed
- Air purifier
- Not needed
Over the last 7 days, the CAMS air-quality model put Fremont's daily AQI at 66 on average, from 52 on Nov 4 to an hourly peak of 93 on Nov 10.
Where Fremont stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Fremont: Critically low
15.4% tree cover against a 30% healthy-neighborhood target, across 4.8 sq mi (12.52 km²) of land.
Trees in this area
48,187
Target trees
93,871
More trees needed
45,684
CO₂ if planted / yr
1,005 t
Deforestation · 2001–2025
How much forest has Fremont lost?
Since 2001, the area within 10 km of Fremont has lost about 196 acres (79 hectares) of forest (about 150 football fields): 2.6% of the forest it had in 2000. Most of it (78%) was deforestation, forest cleared for good, mainly for farms, pasture and plantations.
2017: satellite photo from July 2017 of a 5 × 5 km area in the city center.
- Forest lost since 2001
- 196 acres (79 ha)about 150 football fields
- Share of its forest
- 2.6%of what there was in 2000
- Cleared for good
- 153 acres (62 ha)deforestation: turned into farms, mines or towns
The worst year was 2001, when about 74 acres (30 hectares) of forest were lost.
Acres of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 70 acres (28 ha) | 3 acres (1 ha) | 74 acres (30 ha) |
| 2002 | under 1 ha | under 1 ha | under 1 ha |
| 2003 | 8 acres (3 ha) | under 1 ha | 8 acres (3 ha) |
| 2004 | 3 acres (1 ha) | 5 acres (2 ha) | 8 acres (3 ha) |
| 2005 | 8 acres (3 ha) | under 1 ha | 9 acres (4 ha) |
| 2006 | 8 acres (3 ha) | under 1 ha | 9 acres (4 ha) |
| 2007 | 8 acres (3 ha) | under 1 ha | 9 acres (4 ha) |
| 2008 | 3 acres (1 ha) | under 1 ha | 3 acres (1 ha) |
| 2009 | under 1 ha | under 1 ha | under 1 ha |
| 2010 | under 1 ha | under 1 ha | 3 acres (1 ha) |
| 2011 | under 1 ha | under 1 ha | under 1 ha |
| 2012 | 13 acres (5 ha) | 13 acres (5 ha) | 26 acres (11 ha) |
| 2013 | 5 acres (2 ha) | under 1 ha | 5 acres (2 ha) |
| 2014 | 22 acres (9 ha) | 10 acres (4 ha) | 31 acres (13 ha) |
| 2015 | under 1 ha | under 1 ha | under 1 ha |
| 2016 | under 1 ha | under 1 ha | under 1 ha |
| 2017 | under 1 ha | under 1 ha | 2 acres (1 ha) |
| 2018 | under 1 ha | under 1 ha | under 1 ha |
| 2019 | under 1 ha | under 1 ha | under 1 ha |
| 2020 | under 1 ha | under 1 ha | under 1 ha |
| 2021 | under 1 ha | under 1 ha | under 1 ha |
| 2022 | under 1 ha | under 1 ha | under 1 ha |
| 2023 | under 1 ha | under 1 ha | under 1 ha |
| 2024 | under 1 ha | under 1 ha | under 1 ha |
| 2025 | under 1 ha | under 1 ha | under 1 ha |
What is causing deforestation around Fremont?
- Farms, pasture and plantationscleared for good67% · 132 acres (54 ha)
- Towns and roadscleared for good11% · 21 acres (9 ha)
- Storms, floods and other natural causescan grow back5.3% · 10 acres (4 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
- 11,300 acres (4,580 ha)
- Forest in 2020
- 12,000 acres (4,850 ha)
- Overall change
- +665 acres (269 ha)more forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Fremont grew from about 11,300 acres (4,580 hectares) to 12,000 acres (4,850 hectares), a net gain of about 665 acres (269 hectares) (+5.9%). New forest grew on about 722 acres (292 hectares), while 57 acres (23 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 Fremont
Same 2 km radius, same index — so they compare directly.
- Hayward15.7 km
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- Tree cover
- 20%
- Air quality
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- Sunnyvale20.4 km
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- Air quality
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- San Jose24.7 km
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- Air quality
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- San Mateo29.7 km
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- Tree cover
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- Air quality
- 37
- Oakland37.8 km
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- Tree cover
- 7%
- Air quality
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- Daly City45.2 km
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- Tree cover
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- Air quality
- 55
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Frequently asked
Questions about Fremont
What is the air quality (AQI) in Fremont right now?
The latest reading for Fremont shows an AQI of 29 (Good), measured Nov 11, 07:00 local time by 4 ground monitoring stations via OpenAQ (the median of their readings; the nearest is Irvington, Fremont (kcafremo271), 1.2 mi (1.9 km) away). The main pollutant is PM2.5. Air quality is satisfactory for everyone.
Is it safe to exercise outside in Fremont today?
At AQI 29 (Good): a good day to be active outside. Windows: open them to air the house. Masks: not needed. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Fremont been like this week?
Over the last 7 days, the CAMS air-quality model put Fremont's daily AQI at 66 on average, from 52 on Nov 4 to an hourly peak of 93 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 Fremont lost since 2001?
Since 2001, the area within 10 km of Fremont has lost about 196 acres (79 hectares) of forest (about 150 football fields): 2.6% of the forest it had in 2000. Most of it (78%) was deforestation, forest cleared for good, mainly for farms, pasture and plantations. Comparing satellite maps from 2000 and 2020, the forest around Fremont grew from about 11,300 acres (4,580 hectares) to 12,000 acres (4,850 hectares), a net gain of about 665 acres (269 hectares) (+5.9%). New forest grew on about 722 acres (292 hectares), while 57 acres (23 hectares) were lost.
What is the tree count in Fremont?
Fremont has an estimated 48,187 trees across the 4.8 sq mi (12.52 km²) of land measured — 15.4% tree cover, 15 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Fremont need?
Fremont needs roughly 45,684 more trees to close a 15-point shortfall against its 30% tree-cover target — about 1,005 t of extra CO₂ absorbed per year once grown.
How are Fremont's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Sundale, 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 Sundale; the tree count is an estimate derived from that cover.
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