Air quality comparison · Costa Rica, 115 km apart
Limón vs San José Air quality index (AQI) today
Limón has cleaner air than San José right now: AQI 18 (Good) against 40 (Good).
Both sit in the same EPA band, so the health advice is the same for each today. Over the past 6 days, on modeled daily averages, Limón averaged AQI 30 against 42, and it was the cleaner of the two on 6 of those days. Limón has lost more forest since 2001. Limón has more tree cover.
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Limón18San José40
Head to head
Limón vs San José at a glance
Limón is ahead on 5 of 6 measures, and San José on 1. The better figure in each row is marked.
| Limón | San José | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 18 (better) | 40 |
| PM2.5Fine particles, µg/m³. | 2.8 (better) | 7.2 |
| Past week's averageUS AQI, 6 days. | 30 (better) | 42 |
| Forest lost since 2001Within 10 km of the center. | 1,620 ha | 1,510 ha (better) |
| Tree coverWithin 2 km of the center. | 36.6% (better) | 13.4% |
| Trees still neededTo reach a healthy canopy. | 0 (better) | 52.1K |
Air quality today
What is the air like in Limón and San José right now?
Limón has cleaner air than San José right now: AQI 18 (Good) against 40 (Good). PM2.5 is setting the index in both.
San José is read from a nearby ground station and Limón is a model estimate, so the two are not quite like for like.
LimónSan José
Concentrations at the same moment as the index above, for the pollutants both places report. Lower is better. The dark marks on the PM2.5 and PM10 rows show the WHO's 24-hour guidelines (15 and 45 µg/m³).
Limón: Estimate · model corrected with 2 station cities within 125 km, e.g. Paraíso and San José. Data: Open-Meteo / CAMS, corrected with 2 ground-station cities within 125 km, US EPA index.
San José: Ground station · NASA GSFC Rutgers Calib. N13, 4.8 km away. Data: OpenAQ · Clarity.
The past week
Which had cleaner air over the past 6 days?
Over the past 6 days, on modeled daily averages, Limón averaged AQI 30 against 42, and it was the cleaner of the two on 6 of those days. A single reading can catch a city on a bad afternoon; the week says whether it was the weather or the place.
- Cleaner days
- Limón6San José0
- Average AQI
- Limón30San José42
- Worst day, AQI
- Limón36San José52
The daily numbers (6 days)
| Day | Limón | San José |
|---|---|---|
| Nov 5 | 30 | 52 |
| Nov 6 | 26 | 47 |
| Nov 7 | 36 | 42 |
| Nov 8 | 31 | 35 |
| Nov 9 | 28 | 42 |
| Nov 10 | 28 | 36 |
Daily averages from the CAMS atmospheric model for both places, so the week compares like with like. They can differ from today's reading at the top of the page wherever that comes from a ground station.
What it means today
Is it safe to go outside in Limón and San José today?
Air quality is satisfactory for everyone. Both are in the same EPA band today (Good), so the advice is the same.
Exercise outdoors
A good day to be active outside.
Windows
Open them to air the house.
Masks
Not needed.
Air purifier
Not needed.
Against everywhere else
How do Limón and San José compare with the rest of the world?
Right now Limón's air is cleaner than 90% of the 5,420 places Airleaf tracks, and San José's is cleaner than 70%. Within Costa Rica, that is 75% and 0% of its 5 measured places.
Cleaner air than…
- Limón
- Beats 90%
- San José
- Beats 70%
More tree cover than…
- Limón
- Beats 79%
- San José
- Beats 30%
Includes model estimates as well as station readings, so it can differ from our most polluted and cleanest air rankings, which use station readings only.
Deforestation · 2001–2025
Which has lost more forest, Limón or San José?
Limón has lost more: about 1,620 ha of forest within 10 km of its center from 2001 to 2025, against 1,510 ha around San José. 1,570 ha of that was cleared for good, for farms, mines or towns.
Measured within 10 km of each center, from the yearly satellite maps of forest loss: a wider circle than the one for tree cover, because forest is usually lost at a city's edges.
Worst year: 2016, with 157 ha lost.
Worst year: 2002, with 355 ha lost.
| Limón | San José | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 1,620 ha | 1,510 ha (better) |
| Share of its forestOf what it had in 2000. | 16% | 13% (better) |
| Cleared for goodTurned into farms, mines or towns. | 1,570 ha | 1,480 ha (better) |
| Recent trend2021–2025 against the five years before. | Slowing down | Too little to call |
| Main known cause | Farms, pasture and plantations (87%) | Towns and roads (70%) |
Satellite timelapses
Watch both change, year by year
A clear satellite photo a year of the land around each city. Press play, turn on the forest cleared since the first year, or drag the before and after.
Limón
2017: satellite photo from January 2017 of a 5 × 5 km area about 5 km south of the city center.
San José
2017: satellite photo from March 2017 of a 5 × 5 km area about 7 km north of the city center.
Trees
Which has more trees, Limón or San José?
Limón has more tree cover: 36.6% of the land within 2 km of its center against 13.4% around San José, or about 85,202 trees against 42,097.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Limón | San José | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 85.2K (better) | 42.1K |
| Trees still neededTo reach the target. Fewer is better. | 0 (better) | 52.1K |
| CO₂ absorbed each yearBy the trees already standing. | 1.9M kg (better) | 926K kg |
Tree cover on the satellite image
The same 2 km radius around each center, with the tree cover the satellite found marked on it.
Reading these numbers
How this comparison is made
Air quality index
The US EPA index, computed from current pollutant concentrations: ground stations where a place has them nearby, and the CAMS atmospheric model everywhere else. It moves hour to hour, so it is a snapshot rather than a verdict on either place. The guideline marks are from the WHO's 2021 air quality guidelines.
Trees and forest
Tree cover is the share of ground under canopy within 2 km of each center, read from Sentinel-2 satellite imagery at 10 m detail. It measures that circle, not the whole municipality, which is what makes the two comparable. Forest loss comes from the University of Maryland's Global Forest Change maps.
More on the method on the About Airleaf page.
Frequently asked
Limón vs San José: your questions answered
Is Limón cleaner than San José?
On air quality, yes, right now: Limón reads AQI 18 against 40, a gap of 22 points on the US EPA index. This is a live reading rather than an annual average, so it can reverse within a day. Over the past 6 days, on modeled daily averages, Limón averaged AQI 30 against 42, and it was the cleaner of the two on 6 of those days.
Is it safe to exercise outdoors in Limón and San José today?
The advice is the same for both today. Air quality is satisfactory for everyone. Limón reads AQI 18 and San José reads AQI 40.
Which has lost more forest, Limón or San José?
Limón has lost more: about 1,620 ha of forest within 10 km of its center from 2001 to 2025, against 1,510 ha around San José. 1,570 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Limón or San José?
Limón has more tree cover: 36.6% of the land within 2 km of its center against 13.4% around San José, or about 85,202 trees against 42,097. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Limón and San José need?
Limón needs about 0 more to reach its canopy target of 30%, and San José about 52,150 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Limón and San José measured the same way?
The method is the same: the US EPA index for air, and Sentinel-2 satellite imagery at 10 m detail over an identical radius for trees. San José is read from a nearby ground station and Limón is a model estimate, so the two are not quite like for like. Nothing is adjusted for population, city limits or climate.
How often does the Limón vs San José comparison update?
The air readings refresh about once an hour, and each reading's local time is shown at the top of the page. Tree cover comes from the latest clear satellite image of each area (Jun 28, 2026 and Jun 28, 2026), and the forest figures are published yearly.
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