Worst air pollution Sant Martí - Barcelona, today and tomorrow
Today (20 September): Air quality in Sant Martí is moderate. AQI, PM2.5, and NO2 are moderate; PM10, O3, and PM1 are fair; SO2, CO, and HCHO are good. Pollution peaks around 1:00 AM (PM2.5: 43.8/100).
Tomorrow (21 September 2026): Air quality in Sant Martí is moderate. All pollutants stay as today. Pollution peaks around 10:00 PM (NO2: 52.0/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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In Sant Martí, construction dust and road traffic are the main local influences on air quality. Levels vary sharply between the busy centre and quieter residential districts. The surrounding hills can trap pollution against the city on still, windless days.
Today - 20 September | Pollution peaks at 01:00
AQI:
Moderate
43.8/100
PM2.5 (fine particles):
Moderate
43.8/100
PM10 (coarse particles):
Fair
24.8/100
NO2 (nitrogen dioxide):
Moderate
41.1/100
O3 (ozone):
Fair
22.4/100
SO2 (sulfur dioxide):
Good
2.8/100
CO (carbon monoxide):
Good
0.7/100
HCHO (formaldehyde):
Good
10.4/100
PM1 (ultrafine particles):
Fair
27.3/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 22:00
AQI:
Moderate
52.0/100
PM2.5 (fine particles):
Moderate
42.7/100
PM10 (coarse particles):
Fair
22.3/100
NO2 (nitrogen dioxide):
Moderate
52.0/100
O3 (ozone):
Fair
25.9/100
SO2 (sulfur dioxide):
Good
3.3/100
CO (carbon monoxide):
Good
0.8/100
HCHO (formaldehyde):
Good
11.0/100
PM1 (ultrafine particles):
Fair
28.1/100
Other Landmarks in Barcelona
Sports venues in Barcelona
Frequently Asked Questions
Is air quality bad in Sant Martí right now?
On 20 September 2026, overall air quality in Sant Martí is moderate. AQI is the main air quality indicator at 43.8/100. Pollution peaks around 1:00 AM (PM2.5: 43.8/100).
Will air quality be worse tomorrow in Sant Martí?
On 21 September 2026, air quality conditions in Sant Martí will be similar to today, with AQI forecast at moderate at 52.0/100. Pollution peaks around 10:00 PM (NO2: 52.0/100).
When is air pollution at its worst in Sant Martí?
What time of year has the cleanest air in Sant Martí? Air quality often reaches its yearly low in the depths of winter, when still, cold air holds local emissions from traffic and heating close to ground level. Spring generally sees a gradual recovery, driven by more frequent rain showers and stronger breezes that prevent pollutants from settling. Summer brings its own challenge in the form of ground-level ozone, which forms readily under strong sunshine and high temperatures, particularly during heatwaves. Autumn usually sees a steady return to cleaner conditions as the ozone-favouring heat of summer fades and rainfall picks up. The Mediterranean coast's sea breezes generally help disperse pollution, though summer tourism traffic and occasional Saharan dust can still push levels up.
Are air quality levels in Sant Martí 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.
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Data provided by Airmine — Last update: 20 September 2026 at 14:33 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.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
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