Worst air pollution Indianapolis, today and tomorrow
Today (20 September): Air quality in Indianapolis is fair. AQI, PM2.5, NO2, O3, and PM1 are fair; PM10, SO2, CO, and HCHO are good. Pollution peaks around 2:00 PM (NO2: 39.2/100).
Tomorrow (21 September 2026): Air quality in Indianapolis is fair. All pollutants stay as today. Pollution peaks around 10:00 PM (NO2: 34.2/100). 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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Indianapolis' air quality reflects the flat Indiana Midwest terrain that allows reasonable wind dispersal, with vehicle emissions from the I-465 beltway and the surrounding interstate network the primary local source. Regional ozone from agricultural and industrial sources across the broader Ohio Valley can elevate summer readings, while the flat landscape prevents the topographic trapping seen in hillier US cities.
Today - 20 September | Pollution peaks at 14:00
AQI:
Fair
39.2/100
PM2.5 (fine particles):
Fair
23.8/100
PM10 (coarse particles):
Good
16.4/100
NO2 (nitrogen dioxide):
Fair
39.2/100
O3 (ozone):
Fair
20.2/100
SO2 (sulfur dioxide):
Good
1.7/100
CO (carbon monoxide):
Good
0.6/100
HCHO (formaldehyde):
Good
3.3/100
PM1 (ultrafine particles):
Fair
34.4/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 22:00
AQI:
Fair
34.2/100
PM2.5 (fine particles):
Fair
22.0/100
PM10 (coarse particles):
Good
16.2/100
NO2 (nitrogen dioxide):
Fair
34.2/100
O3 (ozone):
Fair
25.5/100
SO2 (sulfur dioxide):
Good
1.7/100
CO (carbon monoxide):
Good
0.6/100
HCHO (formaldehyde):
Good
3.9/100
PM1 (ultrafine particles):
Fair
22.6/100
Pollen forecast in Indianapolis
View pollen forecastAir quality forecasts for neighbourhoods and landmarks in Indianapolis
Frequently Asked Questions
Is air quality bad in Indianapolis right now?
On 20 September 2026, overall air quality in Indianapolis is fair. AQI is the main air quality indicator at 39.2/100. Pollution peaks around 2:00 PM (NO2: 39.2/100).
Will air quality be worse tomorrow in Indianapolis?
On 21 September 2026, air quality conditions in Indianapolis will be similar to today, with AQI forecast at fair at 34.2/100. Pollution peaks around 10:00 PM (NO2: 34.2/100).
When is air pollution at its worst in Indianapolis?
Indianapolis sees air quality change through the year. In short, between summer ozone and occasional winter inversions, spring and fall are the year's cleanest stretch, whereas prolonged summer heat waves are when air quality most often dips into unhealthy territory. Lake-effect winds can help clear the air on many days near the Great Lakes shoreline.
Are air quality levels in Indianapolis 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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