Worst air pollution Viseu, today and tomorrow

Today (21 July): Air quality in Viseu is medium. AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 3:00 PM (O3: 41.8/100).
Tomorrow (22 July 2026): Air quality in Viseu is fair. AQI worsens to fair; O3 increases to fair; all other pollutants stay as today. Pollution peaks around 3:00 PM (O3: 38.8/100). 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

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Viseu's air quality benefits from its elevated Dão river valley position at 483 metres in the Beira Alta highlands, with consistent Atlantic westerlies from the Portuguese coast providing reliable ventilation across this major wine and dairy producing region. Vehicle traffic on the A25 motorway and surrounding agricultural and manufacturing industry contribute the primary local emissions, while the elevated interior plateau position generally maintains Viseu among Portugal's cleaner regional capital urban environments.

Today - 21 July | Pollution peaks at 15:00

AQI:

Medium

41.8/100

PM2.5 (fine particles):

Good

15.9/100

PM10 (coarse particles):

Good

11.5/100

NO2 (nitrogen dioxide):

Good

5.8/100

O3 (ozone):

Medium

41.8/100

SO2 (sulfur dioxide):

Good

0.8/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

8.0/100

PM1 (ultrafine particles):

Good

13.0/100

Levels show the poorest local air quality during the day

Tomorrow - 22 July | Pollution peaks at 15:00

AQI:

Fair

38.8/100

PM2.5 (fine particles):

Good

13.6/100

PM10 (coarse particles):

Good

11.9/100

NO2 (nitrogen dioxide):

Good

8.5/100

O3 (ozone):

Fair

38.8/100

SO2 (sulfur dioxide):

Good

0.7/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

7.6/100

PM1 (ultrafine particles):

Good

8.6/100

Pollen forecast in Viseu

View pollen forecast

Frequently Asked Questions

Is air quality bad in Viseu right now?

On 21 July 2026, overall air quality in Viseu is medium. AQI is the main air quality indicator at 41.8/100. Pollution peaks around 3:00 PM (O3: 41.8/100).

Will air quality be worse tomorrow in Viseu?

On 22 July 2026, air quality conditions in Viseu will be worse than today, with AQI forecast at fair at 38.8/100. Pollution peaks around 3:00 PM (O3: 38.8/100).

When is air pollution at its worst in Viseu?

People in Viseu tend to notice reduced air quality when local tree and grass pollen peaks, or because of vehicle traffic on the A25 motorway and neighbouring agricultural and manufacturing industry; outside those spells, this remains one of the more consistently clean-air places to be.

Are air quality levels in Viseu 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 Portugal?

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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