Air quality in Chicago today
The air in Chicago (United States) now and over the next 48 hours: the US AQI and the European AQI, fine particles (PM2.5, PM10), ozone and nitrogen dioxide, compared with the WHO 2021 guidelines, with what it means for outdoor sport, children, older people and open windows.
These numbers are more than 7 hours old, so they are hidden. Open the live map for the current air. Open the air map centred on Chicago
AQI right now
Moderate. Main pollutant: Nitrogen dioxide (NO₂), 1.7× the WHO guideline.
What to do today
- Outdoor sport Fine for almost everyone; the very sensitive may shorten long hard sessions.
- Children, older people, asthma Unusually sensitive people: watch for coughing or shortness of breath.
- Windows Open; prefer airing when the AQI is lowest (see the hours below).
AQI in Chicago hour by hour, next 48 hours
- Good
- Moderate
- Unhealthy for sensitive groups
- Unhealthy
- Very unhealthy
- Hazardous
Cleanest hour in the next 24 h: Sat 19:00 (AQI 60). Worst hour: Sun 07:00 (AQI 70).
US AQI per hour, local time. Bars coloured by category.
Compared with the WHO 2021 guidelines
| Pollutant | Next 24 h | WHO guideline | Ratio |
|---|---|---|---|
| PM2.5 | 19 µg/m³ | 15 µg/m³ | 1.2× |
| PM10 | 19 µg/m³ | 45 µg/m³ | within |
| Nitrogen dioxide (NO₂) | 43 µg/m³ | 25 µg/m³ | 1.7× |
| Ozone (O₃) | 59 µg/m³ | 100 µg/m³ | within |
PM2.5, PM10 and NO₂: 24-hour mean of the forecast against the 24-hour guideline; ozone: highest 8-hour mean against the 8-hour guideline.
Forecast for Sat 19:00 local time · updated 2026-10-25 00:41 UTC
Air quality map around Chicago
Live PM2.5 field (NOAA GEFS-Aerosols): a different model, so it can disagree with the numbers above by a few units.
More about Chicago
Bad air alert for Chicago
Air quality alerts are part of LayEarth Pro: one push the evening before the forecast US AQI in your city goes above your level, so you can move a run, a school trip or an open window in time. 7-day free trial, then 9 USD a month.
Questions
- What is the AQI in Chicago right now?
- US AQI 60 (Moderate), European AQI 59; PM2.5 19 µg/m³ (Sat 19:00).
- Is it safe to exercise outdoors in Chicago today?
- Fine for almost everyone; the very sensitive may shorten long hard sessions.
- What is the main pollutant in Chicago?
- Nitrogen dioxide (NO₂), 1.7× the WHO guideline.
- Where do the numbers come from?
- The CAMS global air-quality forecast of the Copernicus Atmosphere Monitoring Service, read through Open-Meteo: a model on a ~40 km grid, not a monitoring station. Where a nearby monitor disagrees, the monitor is right.
Nearby cities
Milwaukee · Indianapolis · Detroit · Cincinnati · St. Louis · Columbus
How it is computed
Hourly CAMS forecast (Copernicus) for the coordinates of Chicago via Open-Meteo; US AQI per the US EPA breakpoints, European AQI per the EEA bands, WHO 2021 air-quality guidelines. The page is rebuilt every 3 hours. Live map.