Worst air pollution Castelldefels, today and tomorrow
Today (9 August): Air quality in Castelldefels is fair. AQI, NO2, and O3 are fair; PM2.5, PM10, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 2:00 PM (O3: 38.1/100).
Tomorrow (10 August 2026): Air quality in Castelldefels is fair. NO2 decreases to good; all other pollutants stay as today. Pollution peaks around 2:00 PM (O3: 34.0/100). Airmine updates local air quality forecasts four times daily.
Get the full experience in the Airmine app.
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
Follow your pollen exposure and performance with the free Airmine–Strava integration. See your pollen and air quality exposure for every Strava activity.
Castelldefels' air quality benefits from its direct Mediterranean coastal position south of Barcelona's El Prat Airport, with consistent sea breezes from the Barcelona Bay providing reliable maritime ventilation. Vehicle traffic on the C-31 and the airport's approaching flight path contribute elevated NOₓ and aviation PM2.5, while the Barcelona Bay sea breeze cycle and the flat delta position generally maintain moderate conditions, though the airport proximity makes Castelldefels one of Catalonia's more aviation-influenced coastal communities.
Today - 9 August | Pollution peaks at 14:00
AQI:
Fair
38.1/100
PM2.5 (fine particles):
Good
10.0/100
PM10 (coarse particles):
Good
3.8/100
NO2 (nitrogen dioxide):
Fair
22.0/100
O3 (ozone):
Fair
38.1/100
SO2 (sulfur dioxide):
Good
5.2/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.3/100
PM1 (ultrafine particles):
Good
6.9/100
Levels show the poorest local air quality during the day
Tomorrow - 10 August | Pollution peaks at 14:00
AQI:
Fair
34.0/100
PM2.5 (fine particles):
Good
10.8/100
PM10 (coarse particles):
Good
3.6/100
NO2 (nitrogen dioxide):
Good
18.4/100
O3 (ozone):
Fair
34.0/100
SO2 (sulfur dioxide):
Good
3.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
4.6/100
PM1 (ultrafine particles):
Good
10.3/100
Pollen forecast in Castelldefels
View pollen forecastFrequently Asked Questions
Is air quality bad in Castelldefels right now?
On 9 August 2026, overall air quality in Castelldefels is fair. AQI is the main air quality indicator at 38.1/100. Pollution peaks around 2:00 PM (O3: 38.1/100).
Will air quality be worse tomorrow in Castelldefels?
On 10 August 2026, air quality conditions in Castelldefels will be similar to today, with AQI forecast at fair at 34.0/100. Pollution peaks around 2:00 PM (O3: 34.0/100).
When is air pollution at its worst in Castelldefels?
Does air quality in Castelldefels vary by season? Winter high-pressure systems tend to produce the year's worst episodes, as still air traps traffic fumes and heating smoke at ground level. Air quality usually improves through spring, helped by more frequent frontal systems that bring rain and stronger winds to disperse local emissions. Hot, stagnant summer air favours ozone formation, and dry vegetation nearby occasionally adds wildfire smoke to the mix during peak heat. By late autumn, air quality is usually back to more moderate levels, though the first cold snaps can bring an early hint of winter's traffic and heating pollution. This Mediterranean location benefits from regular sea breezes, though summer's higher traffic volumes and occasional Saharan dust events can offset that.
Are air quality levels in Castelldefels 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.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
Want to see air quality forecasts for other cities in Spain?
Check air quality in other popular cities:
Data provided by Airmine — Last update: 10 August 2026 at 02:34 CEST (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.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
Get the full experience in the Airmine app.