Worst air pollution Alton, today and tomorrow
Today (16 July): Air quality in Alton is medium. AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 8:00 AM (O3: 48.6/100).
Tomorrow (17 July 2026): Air quality in Alton is medium. All pollutants stay as today. Pollution peaks around 7:00 AM (O3: 51.8/100). 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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Alton's air quality in Illinois reflects the Mississippi River valley position near the Missouri border, with vehicle emissions from the Great River Road and surrounding industrial and logistics operations — including the historic Alton Steel operations legacy — contributing local sources. The Mississippi bluffs create topographic variation, while the broader Mississippi Valley industrial airshed and summer regional ozone from agricultural sources are the primary air quality concerns throughout the year.
Today - 16 July | Pollution peaks at 08:00
AQI:
Medium
48.6/100
PM2.5 (fine particles):
Good
13.8/100
PM10 (coarse particles):
Good
12.2/100
NO2 (nitrogen dioxide):
Good
5.8/100
O3 (ozone):
Medium
48.6/100
SO2 (sulfur dioxide):
Good
1.1/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
8.4/100
PM1 (ultrafine particles):
Good
9.6/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 07:00
AQI:
Medium
51.8/100
PM2.5 (fine particles):
Good
13.8/100
PM10 (coarse particles):
Good
8.4/100
NO2 (nitrogen dioxide):
Good
5.6/100
O3 (ozone):
Medium
51.8/100
SO2 (sulfur dioxide):
Good
0.9/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
9.8/100
PM1 (ultrafine particles):
Good
9.1/100
Pollen forecast in Alton
View pollen forecastFrequently Asked Questions
Is air quality bad in Alton right now?
On 16 July 2026, overall air quality in Alton is medium. AQI is the main air quality indicator at 48.6/100. Pollution peaks around 8:00 AM (O3: 48.6/100).
Will air quality be worse tomorrow in Alton?
On 17 July 2026, air quality conditions in Alton will be similar to today, with AQI forecast at medium at 51.8/100. Pollution peaks around 7:00 AM (O3: 51.8/100).
When is air pollution at its worst in Alton?
Alton experiences a distinct seasonal swing in air quality, as the cleanest stretches usually come in spring and fall, between the summer ozone season and the calmer winter pollution episodes; by contrast, summer heat waves are the main driver of poor air quality, as ozone builds under stagnant, humid conditions. Calm, cold winter spells can occasionally allow local pollution to build up before the next weather system clears it.
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.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 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.
For long term forecasts and maps, see the Airmine app