City report · Costa Rica
San José Air quality today
Air quality in San José currently reads AQI 40 (Good): Air quality is satisfactory for everyone.
Air quality right now
AQI 40
Good
- PM2.5, fine particles (µg/m³)
- 7.2
- tree cover
- 13.4%
- trees in this area
- 42.1K
- more trees needed
- 52.1K
Measured across a 2 km radius around San José, Merced, Costa Rica (12.57 km²), from a satellite image of Jun 28, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
San José · AQI 40 (Good)
San José's tree count comes to 42,097 trees across 12.57 km², 17 points below the 30% tree-cover level considered healthy for this area, so roughly 52,150 more trees would close the gap.
Air quality detail
Air quality in San José today: AQI 40, Good
Main pollutant: PM2.5 · Observed Nov 11, 10:06 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · NASA GSFC Rutgers Calib. N13, 4.8 km away
Health signal
Air quality is satisfactory for everyone.
PM2.5
7.2
PM10
—
NO₂
—
O₃
—
SO₂
—
CO
—
Data: OpenAQ · Clarity
- 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 San José's daily AQI at 44 on average, from 35 on Nov 8 to an hourly peak of 64 on Nov 4.
Where San José stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in San José: Critically low
13.4% tree cover against a 30% healthy-neighborhood target, across 12.57 km².
Trees in this area
42,097
Target trees
94,247
More trees needed
52,150
CO₂ if planted / yr
1,147 t
Deforestation · 2001–2025
How much forest has San José lost?
Since 2001, the area within 10 km of San José has lost about 1,510 hectares of forest (about 2,100 football pitches): 13% of the forest it had in 2000. Most of it (98%) was deforestation, forest cleared for good, mainly for towns and roads.
2017: satellite photo from March 2017 of a 5 × 5 km area about 7 km north of the city center.
- Forest lost since 2001
- 1,510 haabout 2,100 football pitches
- Share of its forest
- 13%of what there was in 2000
- Cleared for good
- 1,480 hadeforestation: turned into farms, mines or towns
The worst year was 2002, when about 355 hectares of forest were lost.
San José's full deforestation reportHectares of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | 90 ha | under 1 ha | 91 ha |
| 2002 | 353 ha | 2 ha | 355 ha |
| 2003 | 36 ha | under 1 ha | 36 ha |
| 2004 | 99 ha | under 1 ha | 100 ha |
| 2005 | 86 ha | 2 ha | 87 ha |
| 2006 | 103 ha | under 1 ha | 103 ha |
| 2007 | 58 ha | under 1 ha | 59 ha |
| 2008 | 99 ha | under 1 ha | 100 ha |
| 2009 | 156 ha | 1 ha | 157 ha |
| 2010 | 26 ha | under 1 ha | 26 ha |
| 2011 | 40 ha | under 1 ha | 41 ha |
| 2012 | 62 ha | under 1 ha | 62 ha |
| 2013 | 14 ha | under 1 ha | 15 ha |
| 2014 | 17 ha | under 1 ha | 17 ha |
| 2015 | 8 ha | under 1 ha | 8 ha |
| 2016 | 18 ha | under 1 ha | 18 ha |
| 2017 | 16 ha | under 1 ha | 16 ha |
| 2018 | 57 ha | under 1 ha | 57 ha |
| 2019 | 29 ha | under 1 ha | 29 ha |
| 2020 | 9 ha | under 1 ha | 9 ha |
| 2021 | 30 ha | 7 ha | 37 ha |
| 2022 | 19 ha | under 1 ha | 19 ha |
| 2023 | 32 ha | 16 ha | 48 ha |
| 2024 | 21 ha | under 1 ha | 21 ha |
| 2025 | 5 ha | under 1 ha | 6 ha |
What is causing deforestation around San José?
- Towns and roadscleared for good70% · 1,060 ha
- Farms, pasture and plantationscleared for good28% · 424 ha
- Loggingcan grow back1.6% · 25 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
- 14,400 ha
- Forest in 2020
- 13,200 ha
- Overall change
- −1,230 haless forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around San José shrank from about 14,400 hectares to 13,200 hectares, a net loss of about 1,230 hectares (−8.5%). New forest grew on about 29 hectares, but 1,260 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 San José
What is the air quality (AQI) in San José right now?
The latest reading for San José shows an AQI of 40 (Good), measured Nov 11, 10:06 local time by the NASA GSFC Rutgers Calib. N13 ground monitoring station, 4.8 km away, via OpenAQ. The main pollutant is PM2.5. Air quality is satisfactory for everyone.
Is it safe to exercise outside in San José today?
At AQI 40 (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 San José been like this week?
Over the last 7 days, the CAMS air-quality model put San José's daily AQI at 44 on average, from 35 on Nov 8 to an hourly peak of 64 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 San José lost since 2001?
Since 2001, the area within 10 km of San José has lost about 1,510 hectares of forest (about 2,100 football pitches): 13% of the forest it had in 2000. Most of it (98%) was deforestation, forest cleared for good, mainly for towns and roads. Comparing satellite maps from 2000 and 2020, the forest around San José shrank from about 14,400 hectares to 13,200 hectares, a net loss of about 1,230 hectares (−8.5%). New forest grew on about 29 hectares, but 1,260 hectares were lost.
What is the tree count in San José?
San José has an estimated 42,097 trees across the 12.57 km² measured — 13.4% tree cover, 17 percentage points short of the 30% tree-cover target set for this area.
How many more trees does San José need?
San José needs roughly 52,150 more trees to close a 17-point shortfall against its 30% tree-cover target — about 1,147 t of extra CO₂ absorbed per year once grown.
How are San José's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near San José, 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 San José; the tree count is an estimate derived from that cover.
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