Worst air pollution Alton, today and tomorrow

Today (9 August): Air quality in Alton is fair. PM1 is fair; AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, and HCHO are good. Pollution peaks around 3:00 PM (O3: 56.2/100).
Tomorrow (10 August 2026): Air quality in Alton is fair. AQI worsens to fair; O3 increases to fair; PM1 decreases to good; all other pollutants stay as today. Pollution peaks around 5:00 PM (O3: 33.3/100). 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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Air quality in Alton is shaped by its location in Hampshire, where vehicle traffic and everyday urban activity dominate local sources. Emissions along the M40 represent the town's main traffic-related pollution source. Light prevailing breezes help ventilate the town centre, keeping air quality at moderate levels typical for the region.

Today - 9 August | Pollution peaks at 15:00

AQI:

Medium

56.2/100

PM2.5 (fine particles):

Good

15.7/100

PM10 (coarse particles):

Good

4.2/100

NO2 (nitrogen dioxide):

Good

0.5/100

O3 (ozone):

Medium

56.2/100

SO2 (sulfur dioxide):

Good

0.1/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

7.8/100

PM1 (ultrafine particles):

Fair

21.5/100

Levels show the poorest local air quality during the day

Tomorrow - 10 August | Pollution peaks at 17:00

AQI:

Fair

33.3/100

PM2.5 (fine particles):

Good

5.2/100

PM10 (coarse particles):

Good

1.9/100

NO2 (nitrogen dioxide):

Good

0.1/100

O3 (ozone):

Fair

33.3/100

SO2 (sulfur dioxide):

Good

0.0/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

4.6/100

PM1 (ultrafine particles):

Good

4.6/100

Pollen forecast in Alton

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Frequently Asked Questions

Is air quality bad in Alton right now?

On 9 August 2026, overall air quality in Alton is fair. PM1 is the main pollutant at 21.5/100. Pollution peaks around 3:00 PM (O3: 56.2/100).

Will air quality be worse tomorrow in Alton?

On 10 August 2026, air quality conditions in Alton will be similar to today, with AQI forecast at fair at 33.3/100. Pollution peaks around 5:00 PM (O3: 33.3/100).

When is air pollution at its worst in Alton?

Here's the thing about Alton: air quality has a clear seasonal rhythm. In summer, ozone can build up on sunny afternoons, though windier, warmer weather usually helps clear traffic-related pollution faster than in winter. In deep winter, a lack of wind lets M40 traffic fumes and woodsmoke settle instead of blowing through. Spring and autumn don't usually cause much concern, sitting comfortably between winter's peak and summer's ozone spikes.

Are air quality levels in Alton 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: 9 August 2026 at 20:27 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.

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