Highest air pollution San José, today and tomorrow
Today (28 June): Air quality in San José is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 10:00 AM (O3: 21.8/100).
Tomorrow (29 June 2026): Air quality in San José is good. AQI improves to good; O3 decreases to good; all other pollutants stay as today. Pollution peaks around 10:00 AM (O3: 19.4/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
San José's air quality reflects the Central Valley of Costa Rica's enclosed basin at 1,170 metres between the Talamanca and Central volcanic ranges, with vehicle traffic on surrounding expressways and the agri-food, pharmaceutical, and services corridor contributing local sources. The enclosed valley's persistent morning inversions trap vehicle and heating emissions, while the surrounding volcano topography creates concentration under calm conditions and Costa Rica's relatively progressive clean energy profile provides somewhat better background conditions than comparable Latin American enclosed valley cities.
Today - 28 June | Pollution peaks at 10:00
AQI:
Fair
21.8/100
PM2.5 (fine particles):
Good
16.8/100
PM10 (coarse particles):
Good
9.8/100
NO2 (nitrogen dioxide):
Good
6.5/100
O3 (ozone):
Fair
21.8/100
SO2 (sulfur dioxide):
Good
0.8/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
10.4/100
PM1 (ultrafine particles):
Good
12.7/100
Levels show the poorest local air quality during the day
Tomorrow - 29 June | Pollution peaks at 10:00
AQI:
Good
19.4/100
PM2.5 (fine particles):
Good
6.4/100
PM10 (coarse particles):
Good
4.3/100
NO2 (nitrogen dioxide):
Good
5.6/100
O3 (ozone):
Good
19.4/100
SO2 (sulfur dioxide):
Good
0.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
9.9/100
PM1 (ultrafine particles):
Good
5.2/100
Pollen forecast in San José
View pollen forecastFrequently Asked Questions
Is air quality bad in San José right now?
On 28 June 2026, overall air quality in San José is fair. AQI is the main air quality indicator at 21.8/100. Pollution peaks around 10:00 AM (O3: 21.8/100).
Will air quality be worse tomorrow in San José?
On 29 June 2026, air quality conditions in San José will be better than today, with AQI forecast at good at 19.4/100. Pollution peaks around 10:00 AM (O3: 19.4/100).
Are air quality levels in San José based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
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Data provided by Airmine — Last update: 28 June 2026 at 18:36 CET (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team