City report · Puerto Rico
San Juan Air quality today
Air quality in San Juan currently reads AQI 60 (Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
AQI 60
Air quality right now
Moderate
- PM2.5, fine particles (µg/m³)
- 14.0
- tree cover
- 8.6%
- trees in this area
- 7.7K
- more trees needed
- 19.2K
Measured across a 1.2 mi (2 km) radius around Puerta de Tierra, San Juan, Puerto Rico (4.9 sq mi), from a satellite image of Sep 18, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
San Juan · AQI 60 (Moderate)
San Juan's tree count comes to 7,727 trees across 1.4 sq mi (3.6 km²) of land, 21 points below the 30% tree-cover level considered healthy for this area, so roughly 19,228 more trees would close the gap.
Air quality detail
Air quality in San Juan today: AQI 60, Moderate
Main pollutant: PM2.5 · Observed Nov 11, 12:00 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Cataño 40, 3.5 mi (5.7 km) away
Health signal
Unusually sensitive people should consider limiting long outdoor exertion.
PM2.5
14.0
PM10
—
NO₂
—
O₃
—
SO₂
—
CO
—
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 San Juan's daily AQI at 31 on average, from 12 on Nov 7 to an hourly peak of 61 on Nov 4.
Where San Juan stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in San Juan: Critically low
8.6% tree cover against a 30% healthy-neighborhood target, across 1.4 sq mi (3.6 km²) of land.
Trees in this area
7,727
Target trees
26,955
More trees needed
19,228
CO₂ if planted / yr
423.0 t
Deforestation · 2001–2025
How much forest has San Juan lost?
Since 2001, the area within 10 km of San Juan has lost about 596 acres (241 hectares) of forest (about 450 football fields): 17% of the forest it had in 2000. Most of it was lost to storms, floods and other natural causes, so much of it can grow back. About 201 acres (81 hectares) (34%) was deforestation: forest cleared for good for farms, mines or towns.
2017: satellite photo from February 2017 of a 5 × 5 km area about 7 km southeast of the city center.
- Forest lost since 2001
- 596 acres (241 ha)about 450 football fields
- Share of its forest
- 17%of what there was in 2000
- Cleared for good
- 201 acres (81 ha)deforestation: turned into farms, mines or towns
The worst year was 2017, when about 437 acres (177 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 | 3 acres (1 ha) | under 1 ha | 4 acres (2 ha) |
| 2002 | under 1 ha | under 1 ha | under 1 ha |
| 2003 | 8 acres (3 ha) | under 1 ha | 8 acres (3 ha) |
| 2004 | 13 acres (5 ha) | under 1 ha | 14 acres (6 ha) |
| 2005 | under 1 ha | under 1 ha | under 1 ha |
| 2006 | 21 acres (8 ha) | under 1 ha | 22 acres (9 ha) |
| 2007 | 5 acres (2 ha) | under 1 ha | 6 acres (2 ha) |
| 2008 | 4 acres (2 ha) | under 1 ha | 5 acres (2 ha) |
| 2009 | 10 acres (4 ha) | under 1 ha | 11 acres (5 ha) |
| 2010 | under 1 ha | under 1 ha | under 1 ha |
| 2011 | 2 acres (1 ha) | under 1 ha | 3 acres (1 ha) |
| 2012 | 2 acres (1 ha) | under 1 ha | 3 acres (1 ha) |
| 2013 | 3 acres (1 ha) | under 1 ha | 3 acres (1 ha) |
| 2014 | 6 acres (2 ha) | 3 acres (1 ha) | 9 acres (4 ha) |
| 2015 | 4 acres (2 ha) | under 1 ha | 4 acres (2 ha) |
| 2016 | 3 acres (1 ha) | under 1 ha | 3 acres (1 ha) |
| 2017 | 90 acres (37 ha) | 347 acres (141 ha) | 437 acres (177 ha) |
| 2018 | 3 acres (1 ha) | 10 acres (4 ha) | 13 acres (5 ha) |
| 2019 | under 1 ha | under 1 ha | under 1 ha |
| 2020 | 6 acres (2 ha) | under 1 ha | 6 acres (3 ha) |
| 2021 | 4 acres (2 ha) | under 1 ha | 4 acres (2 ha) |
| 2022 | under 1 ha | under 1 ha | under 1 ha |
| 2023 | 4 acres (2 ha) | 23 acres (9 ha) | 27 acres (11 ha) |
| 2024 | under 1 ha | under 1 ha | 2 acres (1 ha) |
| 2025 | 3 acres (1 ha) | under 1 ha | 3 acres (1 ha) |
What is causing deforestation around San Juan?
- Storms, floods and other natural causescan grow back64% · 383 acres (155 ha)
- Towns and roadscleared for good30% · 176 acres (71 ha)
- Farms, pasture and plantationscleared for good4.2% · 25 acres (10 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
- 1,500 acres (607 ha)
- Forest in 2020
- 1,430 acres (579 ha)
- Overall change
- −69 acres (28 ha)less forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around San Juan shrank from about 1,500 acres (607 hectares) to 1,430 acres (579 hectares), a net loss of about 69 acres (28 hectares) (−4.6%). New forest grew on about 114 acres (46 hectares), but 185 acres (75 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 San Juan
Same 2 km radius, same index — so they compare directly.
- Mayagüez113.0 km
Puerto Rico
- Tree cover
- 48%
- Air quality
- 55
- Charlotte Amalie124.7 km
U.S. Virgin Islands
- Tree cover
- 49%
- Air quality
- 52
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Frequently asked
Questions about San Juan
What is the air quality (AQI) in San Juan right now?
The latest reading for San Juan shows an AQI of 60 (Moderate), measured Nov 11, 12:00 local time by the Cataño 40 ground monitoring station, 3.5 mi (5.7 km) away, via OpenAQ. The main pollutant is PM2.5. Unusually sensitive people should consider limiting long outdoor exertion.
Is it safe to exercise outside in San Juan today?
At AQI 60 (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 San Juan been like this week?
Over the last 7 days, the CAMS air-quality model put San Juan's daily AQI at 31 on average, from 12 on Nov 7 to an hourly peak of 61 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 Juan lost since 2001?
Since 2001, the area within 10 km of San Juan has lost about 596 acres (241 hectares) of forest (about 450 football fields): 17% of the forest it had in 2000. Most of it was lost to storms, floods and other natural causes, so much of it can grow back. About 201 acres (81 hectares) (34%) was deforestation: forest cleared for good for farms, mines or towns. Comparing satellite maps from 2000 and 2020, the forest around San Juan shrank from about 1,500 acres (607 hectares) to 1,430 acres (579 hectares), a net loss of about 69 acres (28 hectares) (−4.6%). New forest grew on about 114 acres (46 hectares), but 185 acres (75 hectares) were lost.
What is the tree count in San Juan?
San Juan has an estimated 7,727 trees across the 1.4 sq mi (3.6 km²) of land measured — 8.6% tree cover, 21 percentage points short of the 30% tree-cover target set for this area.
How many more trees does San Juan need?
San Juan needs roughly 19,228 more trees to close a 21-point shortfall against its 30% tree-cover target — about 423.0 t of extra CO₂ absorbed per year once grown.
How are San Juan's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Puerta de Tierra, 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 Puerta de Tierra; the tree count is an estimate derived from that cover.
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