Worst air pollution Castelo Branco, today and tomorrow
Today (21 July): Air quality in Castelo Branco is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 2:00 PM (O3: 36.3/100).
Tomorrow (22 July 2026): Air quality in Castelo Branco is fair. All pollutants stay as today. Pollution peaks around 3:00 PM (O3: 39.1/100). 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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Castelo Branco's air quality benefits from its elevated Beira Baixa position at 379 metres near the Spanish border, with consistent Atlantic westerlies providing reliable ventilation across the flat Tagus interior plateau. Vehicle traffic on the A23 motorway and the surrounding agricultural and light manufacturing operations contribute the primary local sources, while the open Iberian plateau and Atlantic westerlies generally maintain Castelo Branco among Portugal's more moderate interior regional capital environments throughout the year.
Today - 21 July | Pollution peaks at 14:00
AQI:
Fair
36.3/100
PM2.5 (fine particles):
Good
15.0/100
PM10 (coarse particles):
Good
11.2/100
NO2 (nitrogen dioxide):
Good
15.7/100
O3 (ozone):
Fair
36.3/100
SO2 (sulfur dioxide):
Good
2.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.8/100
PM1 (ultrafine particles):
Good
9.3/100
Levels show the poorest local air quality during the day
Tomorrow - 22 July | Pollution peaks at 15:00
AQI:
Fair
39.1/100
PM2.5 (fine particles):
Good
16.5/100
PM10 (coarse particles):
Good
9.9/100
NO2 (nitrogen dioxide):
Good
12.5/100
O3 (ozone):
Fair
39.1/100
SO2 (sulfur dioxide):
Good
2.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.2/100
PM1 (ultrafine particles):
Good
11.1/100
Pollen forecast in Castelo Branco
View pollen forecastFrequently Asked Questions
Is air quality bad in Castelo Branco right now?
On 21 July 2026, overall air quality in Castelo Branco is fair. AQI is the main air quality indicator at 36.3/100. Pollution peaks around 2:00 PM (O3: 36.3/100).
Will air quality be worse tomorrow in Castelo Branco?
On 22 July 2026, air quality conditions in Castelo Branco will be similar to today, with AQI forecast at fair at 39.1/100. Pollution peaks around 3:00 PM (O3: 39.1/100).
When is air pollution at its worst in Castelo Branco?
Reduced air quality in Castelo Branco is most likely when local tree and grass pollen peaks, alongside periods of vehicle traffic on the A23 motorway and the local agricultural and light manufacturing operations; the rest of the calendar year, the local setting keeps things noticeably clearer than average.
Are air quality levels in Castelo Branco 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: 21 July 2026 at 16:20 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.
For long term forecasts and maps, see the Airmine app