City report · California, United States
Fresno Air quality today
Air quality in Fresno currently reads AQI 78 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Air quality right now
AQI 78
Moderate
- PM2.5, fine particles (µg/m³)
- 23.6
- tree cover
- 11.9%
- trees in this area
- 37.4K
- more trees needed
- 56.9K
Measured across a 1.2 mi (2 km) radius around Roosevelt, Fresno, CA, 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.
Fresno · AQI 78 (Moderate)
Fresno's tree count comes to 37,385 trees across 4.9 sq mi (12.57 km²), 18 points below the 30% tree-cover level considered healthy for this area, so roughly 56,863 more trees would close the gap.
Air quality detail
Air quality in Fresno today: AQI 78, Moderate
Main pollutant: PM2.5 · Observed Nov 11, 06:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Fresno-Foundry Park, 2.5 mi (4.1 km) away · median of 5 stations
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
23.6
PM10
38.0
NO₂
24.6
O₃
17.7
SO₂
1.6
CO
286.4
Data: OpenAQ · AirNow
- 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 Fresno's daily AQI at 60 on average, from 50 on Nov 4 to an hourly peak of 100 on Nov 6.
Where Fresno stands: the most polluted cities in the world right now · the cleanest
City air guide
Why is Fresno's air so polluted?
Right now
- Today's AQI in Fresno is 78, moderate, mostly from PM2.5.
- Over the past 7 days, the daily average was 60.
- November is in Fresno's usual season for winter particle pollution (November to February), so expect bad days to come and go until it ends.
Fresno sits in the San Joaquin Valley, where the surrounding mountain ranges trap air pollution [1]. Its air has two bad seasons: smoke and fine particles in winter, when cold, still weather holds them close to the ground [2], and ozone in summer. The American Lung Association ranks the Fresno area 4th worst in the US for year-round particle pollution and 5th for ozone, from 2022–2024 data [3].
Why does the valley trap pollution?
The San Joaquin Valley is surrounded by mountain ranges, and they keep polluted air from blowing away [1]. In winter, cold and still weather adds a lid: wood smoke and other fine particles stay close to the ground, where they can reach unhealthy levels [2].
Where does the pollution come from?
Heavy truck traffic on Interstate 5 and Highway 99, diesel locomotives, tractors and irrigation pumps all add to the valley's air, along with wood-burning stoves and fireplaces in winter [1].
How bad is it compared with the rest of the US?
Among the worst. In the Lung Association's 2026 report, the Fresno area ranked 4th most polluted for year-round particle pollution, 6th for short-term particle spikes (16.5 unhealthy days a year) and 5th for ozone (54.5 unhealthy days a year), based on 2022–2024 data [3].
It's improving, though: the same report says Fresno recorded its lowest annual particle pollution level and its cleanest-ever result for short-term particles [3].
What is being done about it?
Every winter, from November 1 through the end of February, the valley's air district posts a daily wood-burning status under its "Check Before You Burn" rule, which limits fireplaces and wood stoves on bad days [2].
It has made a measurable difference. After the rule was fully in place in 2003, fine particle pollution fell 12% across the valley, hospital admissions for heart and blood-vessel problems among people 65 and over fell 7%, and admissions for ischemic heart disease fell 16% [2].
How to protect yourself in Fresno
On winter days with a no-burn status or a high AQI, keep the windows shut and run a HEPA air purifier in the room you use most, sized for that room. Don't add to it indoors: skip the fireplace, candles and frying.
In summer, ozone builds through hot, sunny afternoons, so exercise in the early morning. Filters and masks don't stop ozone; staying indoors in the afternoon does. When wildfire smoke drifts in, treat it like winter smog: windows shut, purifier on high.
Sources
- [1] US Environmental Protection Agency, EPA Activities for Cleaner Air (San Joaquin Valley) (archived January 2021)
- [2] California Air Resources Board, Hospital admissions drop and air quality improves with fireplace, wood burning restrictions (November 2015)
- [3] American Lung Association, California Clean Air Progress at Risk: "State of the Air" Highlights Local Pollution Progress and Challenges (April 2026)
Last reviewed . The figures in the box at the top update with every new reading; the guide itself is checked against its sources at least once a year, before the city's bad-air season.
Tree cover detail
Tree cover in Fresno: Critically low
11.9% tree cover against a 30% healthy-neighborhood target, across 4.9 sq mi (12.57 km²).
Trees in this area
37,385
Target trees
94,248
More trees needed
56,863
CO₂ if planted / yr
1,251 t
Deforestation · 2001–2025
How much forest has Fresno lost?
Since 2001, the area within 10 km of Fresno has lost about 743 acres (301 hectares) of forest (about 560 football fields): 79% of the forest it had in 2000. Most of it (over 99%) was deforestation, forest cleared for good, mainly for farms, pasture and plantations.
2017: satellite photo from August 2017 of a 5 × 5 km area in the city center.
- Forest lost since 2001
- 743 acres (301 ha)about 560 football fields
- Share of its forest
- 79%of what there was in 2000
- Cleared for good
- 740 acres (299 ha)deforestation: turned into farms, mines or towns
The worst year was 2004, when about 119 acres (48 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 | 21 acres (8 ha) | under 1 ha | 21 acres (8 ha) |
| 2002 | 24 acres (10 ha) | under 1 ha | 24 acres (10 ha) |
| 2003 | 21 acres (8 ha) | under 1 ha | 22 acres (9 ha) |
| 2004 | 119 acres (48 ha) | under 1 ha | 119 acres (48 ha) |
| 2005 | 72 acres (29 ha) | under 1 ha | 73 acres (29 ha) |
| 2006 | 78 acres (32 ha) | under 1 ha | 78 acres (32 ha) |
| 2007 | 53 acres (21 ha) | under 1 ha | 53 acres (21 ha) |
| 2008 | 82 acres (33 ha) | under 1 ha | 82 acres (33 ha) |
| 2009 | 113 acres (46 ha) | under 1 ha | 114 acres (46 ha) |
| 2010 | 33 acres (13 ha) | under 1 ha | 33 acres (13 ha) |
| 2011 | 48 acres (19 ha) | under 1 ha | 48 acres (19 ha) |
| 2012 | 15 acres (6 ha) | under 1 ha | 15 acres (6 ha) |
| 2013 | 11 acres (5 ha) | under 1 ha | 11 acres (5 ha) |
| 2014 | 17 acres (7 ha) | under 1 ha | 17 acres (7 ha) |
| 2015 | 3 acres (1 ha) | under 1 ha | 3 acres (1 ha) |
| 2016 | 5 acres (2 ha) | under 1 ha | 5 acres (2 ha) |
| 2017 | 8 acres (3 ha) | under 1 ha | 8 acres (3 ha) |
| 2018 | 6 acres (3 ha) | under 1 ha | 6 acres (3 ha) |
| 2019 | 4 acres (2 ha) | under 1 ha | 4 acres (2 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 | 2 acres (1 ha) | under 1 ha | 2 acres (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 Fresno?
- Farms, pasture and plantationscleared for good77% · 576 acres (233 ha)
- Towns and roadscleared for good22% · 163 acres (66 ha)
Also: 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
- 2,830 acres (1,150 ha)
- Forest in 2020
- 2,730 acres (1,110 ha)
- Overall change
- −99 acres (40 ha)less forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Fresno shrank from about 2,830 acres (1,150 hectares) to 2,730 acres (1,110 hectares), a net loss of about 99 acres (40 hectares) (−3.5%). New forest grew on about 223 acres (90 hectares), but 321 acres (130 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 Fresno
Same 2 km radius, same index — so they compare directly.
- Visalia63.2 km
United States
- Tree cover
- 13%
- Air quality
- 62
- Modesto146.9 km
United States
- Tree cover
- 26%
- Air quality
- 77
- Bakersfield167.2 km
United States
- Tree cover
- 8%
- Air quality
- 82
- Salinas168.0 km
United States
- Tree cover
- 5%
- Air quality
- 23
- Stockton190.0 km
United States
- Tree cover
- 16%
- Air quality
- 60
- San Jose199.5 km
United States
- Tree cover
- 17%
- Air quality
- 55
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Frequently asked
Questions about Fresno
What is the air quality (AQI) in Fresno right now?
The latest reading for Fresno shows an AQI of 78 (Moderate), measured Nov 11, 06:00 local time by 5 ground monitoring stations via OpenAQ (the median of their readings; the nearest is Fresno-Foundry Park, 2.5 mi (4.1 km) away). The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in Fresno today?
At AQI 78 (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 Fresno been like this week?
Over the last 7 days, the CAMS air-quality model put Fresno's daily AQI at 60 on average, from 50 on Nov 4 to an hourly peak of 100 on Nov 6. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
Why is Fresno's air quality so bad?
Fresno sits in the San Joaquin Valley, where the surrounding mountains trap pollution from trucks on I-5 and Highway 99, farm and rail diesel engines and winter wood smoke. Cold, still winter weather holds fine particles near the ground, and summer heat makes ozone.
When is the air worst in Fresno?
Twice a year: fine particle pollution in winter, roughly November to February, and ozone in the summer.
Can I use my fireplace in Fresno in winter?
Only when the day's status allows it. From November 1 to the end of February, the San Joaquin Valley air district posts a daily wood-burning status under its Check Before You Burn rule; check it before lighting a fire.
How much forest has the area around Fresno lost since 2001?
Since 2001, the area within 10 km of Fresno has lost about 743 acres (301 hectares) of forest (about 560 football fields): 79% of the forest it had in 2000. Most of it (over 99%) was deforestation, forest cleared for good, mainly for farms, pasture and plantations. Comparing satellite maps from 2000 and 2020, the forest around Fresno shrank from about 2,830 acres (1,150 hectares) to 2,730 acres (1,110 hectares), a net loss of about 99 acres (40 hectares) (−3.5%). New forest grew on about 223 acres (90 hectares), but 321 acres (130 hectares) were lost.
What is the tree count in Fresno?
Fresno has an estimated 37,385 trees across the 4.9 sq mi (12.57 km²) measured — 11.9% tree cover, 18 percentage points short of the 30% tree-cover target set for this area.
How many more trees does Fresno need?
Fresno needs roughly 56,863 more trees to close a 18-point shortfall against its 30% tree-cover target — about 1,251 t of extra CO₂ absorbed per year once grown.
How are Fresno's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Roosevelt, 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 Roosevelt; the tree count is an estimate derived from that cover.
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