City report · California, United States
El Cajon Air quality today
Air quality in El Cajon currently reads AQI 21 (Good): Air quality is satisfactory for everyone.
Air quality right now
AQI 21
Good
- PM2.5, fine particles (µg/m³)
- 3.6
- tree cover
- 4.1%
- trees in this area
- 12.9K
- more trees needed
- 81.4K
Measured across a 1.2 mi (2 km) radius around El Cajon, CA, USA (4.9 sq mi), from a satellite image of Sep 14, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
El Cajon · AQI 21 (Good)
El Cajon's tree count comes to 12,881 trees across 4.9 sq mi (12.57 km²), 26 points below the 30% tree-cover level considered healthy for this area, so roughly 81,367 more trees would close the gap.
Air quality detail
Air quality in El Cajon today: AQI 21, Good
Main pollutant: Ozone · Observed Nov 11, 06:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Alpine, 11.7 mi (18.9 km) away · median of 7 stations
Health signal
Air quality is satisfactory for everyone.
PM2.5
3.6
PM10
9.5
NO₂
—
O₃
47.1
SO₂
—
CO
—
Data: OpenAQ · AirNow
- 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 El Cajon's daily AQI at 28 on average, from 20 on Nov 8 to an hourly peak of 65 on Nov 4.
Where El Cajon stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in El Cajon: Critically low
4.1% tree cover against a 30% healthy-neighborhood target, across 4.9 sq mi (12.57 km²).
Trees in this area
12,881
Target trees
94,248
More trees needed
81,367
CO₂ if planted / yr
1,790 t
Deforestation · 2001–2025
How much forest has El Cajon lost?
Since 2001, the area within 10 km of El Cajon has lost about 415 acres (168 hectares) of forest (about 310 football fields): 36% of the forest it had in 2000. Most of it (50%) was deforestation, forest cleared for good, mainly for farms, pasture and plantations.
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
- Forest lost since 2001
- 415 acres (168 ha)about 310 football fields
- Share of its forest
- 36%of what there was in 2000
- Cleared for good
- 209 acres (85 ha)deforestation: turned into farms, mines or towns
The worst year was 2003, when about 106 acres (43 hectares) of forest were lost, mostly to wildfires.
Acres of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 8 acres (3 ha) | 10 acres (4 ha) | 18 acres (7 ha) |
| 2002 | under 1 ha | under 1 ha | under 1 ha |
| 2003 | 36 acres (14 ha) | 71 acres (29 ha) | 106 acres (43 ha) |
| 2004 | 5 acres (2 ha) | 39 acres (16 ha) | 44 acres (18 ha) |
| 2005 | under 1 ha | under 1 ha | under 1 ha |
| 2006 | 12 acres (5 ha) | 3 acres (1 ha) | 15 acres (6 ha) |
| 2007 | under 1 ha | 36 acres (14 ha) | 36 acres (14 ha) |
| 2008 | 22 acres (9 ha) | 27 acres (11 ha) | 50 acres (20 ha) |
| 2009 | under 1 ha | under 1 ha | under 1 ha |
| 2010 | 5 acres (2 ha) | under 1 ha | 6 acres (2 ha) |
| 2011 | 18 acres (7 ha) | under 1 ha | 18 acres (7 ha) |
| 2012 | 24 acres (10 ha) | under 1 ha | 25 acres (10 ha) |
| 2013 | under 1 ha | 4 acres (2 ha) | 4 acres (2 ha) |
| 2014 | 12 acres (5 ha) | under 1 ha | 13 acres (5 ha) |
| 2015 | 16 acres (7 ha) | under 1 ha | 18 acres (7 ha) |
| 2016 | 34 acres (14 ha) | 9 acres (4 ha) | 44 acres (18 ha) |
| 2017 | 3 acres (1 ha) | under 1 ha | 4 acres (2 ha) |
| 2018 | 6 acres (2 ha) | under 1 ha | 6 acres (2 ha) |
| 2019 | 4 acres (2 ha) | under 1 ha | 5 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 | 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 El Cajon?
- Farms, pasture and plantationscleared for good47% · 196 acres (80 ha)
- Wildfirescan grow back37% · 152 acres (62 ha)
- Loggingcan grow back9.3% · 39 acres (16 ha)
Also: towns and roads, storms, floods and other natural causes, 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
- 11,100 acres (4,490 ha)
- Forest in 2020
- 11,200 acres (4,540 ha)
- Overall change
- +141 acres (57 ha)more forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around El Cajon stayed about the same size, at about 11,200 acres (4,540 hectares): new forest grew on about 405 acres (164 hectares), and about 264 acres (107 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 El Cajon
Same 2 km radius, same index — so they compare directly.
- Chula Vista20.6 km
United States
- Tree cover
- 6%
- Air quality
- 22
- San Diego20.9 km
United States
- Tree cover
- 7%
- Air quality
- 22
- Tijuana32.7 km
Mexico
- Tree cover
- 5%
- Air quality
- 62
- Escondido37.9 km
United States
- Tree cover
- 9%
- Air quality
- 20
- Rosarito48.9 km
Mexico
- Tree cover
- 2%
- Air quality
- 62
- Vista52.1 km
United States
- Tree cover
- 14%
- Air quality
- 39
Build your own
Compare El Cajon with anywhere
This place
El Cajon
Use this data
Put El Cajon's numbers on your site
Free to embed. Updates itself as the measurement refreshes.
Frequently asked
Questions about El Cajon
What is the air quality (AQI) in El Cajon right now?
The latest reading for El Cajon shows an AQI of 21 (Good), measured Nov 11, 06:00 local time by 7 ground monitoring stations via OpenAQ (the median of their readings; the nearest is Alpine, 11.7 mi (18.9 km) away). The main pollutant is Ozone. Air quality is satisfactory for everyone.
Is it safe to exercise outside in El Cajon today?
At AQI 21 (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 El Cajon been like this week?
Over the last 7 days, the CAMS air-quality model put El Cajon's daily AQI at 28 on average, from 20 on Nov 8 to an hourly peak of 65 on Nov 4. No day averaged above 100, the level where the air turns unhealthy for sensitive groups.
How much forest has the area around El Cajon lost since 2001?
Since 2001, the area within 10 km of El Cajon has lost about 415 acres (168 hectares) of forest (about 310 football fields): 36% of the forest it had in 2000. Most of it (50%) was deforestation, forest cleared for good, mainly for farms, pasture and plantations. Comparing satellite maps from 2000 and 2020, the forest around El Cajon stayed about the same size, at about 11,200 acres (4,540 hectares): new forest grew on about 405 acres (164 hectares), and about 264 acres (107 hectares) were lost.
What is the tree count in El Cajon?
El Cajon has an estimated 12,881 trees across the 4.9 sq mi (12.57 km²) measured — 4.1% tree cover, 26 percentage points short of the 30% tree-cover target set for this area.
How many more trees does El Cajon need?
El Cajon needs roughly 81,367 more trees to close a 26-point shortfall against its 30% tree-cover target — about 1,790 t of extra CO₂ absorbed per year once grown.
How are El Cajon's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near El Cajon, 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 El Cajon; the tree count is an estimate derived from that cover.
See your own area
What does your neighborhood look like?
Pick any point and radius to get the same air-quality and tree-cover breakdown.
Check my address