Chicago air quality
Illinois, United States · Live AQI and hourly forecast for the next 5 days · updated Sat 7:00 PM local time
Good
Great air. A perfect time to be outside.
- Next 24 hours
- 34–56US AQI, highest around Sun 11:00 AM
- Best time outside
- Sun 1:00 AM–4:00 AMUS AQI about 35
- PM2.5 vs WHO guideline
- 0.8×12 µg/m³ over 24 h, guideline 15
- Cigarette equivalent
- ≈ 0.6 a dayBerkeley Earth rule of thumb
- European AQI
- Fairlevel 2 of 6
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Pollutants in Chicago right now
| Pollutant | Now | Next 24 h vs WHO | US AQI band |
|---|---|---|---|
| Fine particles (PM2.5) | 7.9 µg/m³ | 0.8× | Good |
| Coarse particles (PM10) | 7.9 µg/m³ | 0.3× | Good |
| Nitrogen dioxide (NO2) | 23 µg/m³ | 1.2× | Good |
| Ozone (O3) | 85 µg/m³ | 1.0× | Good |
| Sulphur dioxide (SO2) | 2.7 µg/m³ | 0.1× | Good |
| Carbon monoxide (CO) | 178 µg/m³ | 0.1× | Good |
| Desert dust | 0 µg/m³ | ||
| Smoke and haze (aerosol optical depth) | 0.09 | ||
| UV index | 0.0 |
“Next 24 h vs WHO” compares the forecast with the World Health Organization’s 2021 guideline levels: 24-hour means of 15 µg/m³ for PM2.5, 45 for PM10, 25 for NO2, 40 for SO2 and 4 mg/m³ for CO, and 100 µg/m³ over 8 hours for ozone. Above 1× is above the guideline.
Next 48 hours
Hourly US AQI. Highest 56 around Sun 11:00 AM, lowest 34 around Sun 2:00 AM.
5-day air quality forecast for Chicago
Daily range of the hourly US AQI, from lowest to highest, on a scale of 0 to 150.
| Day | US AQI | At worst | PM2.5 avg | |
|---|---|---|---|---|
| Sat, Sep 26 | 30–46 | 5.8 | ||
| Sun, Sep 27 | 34–56 | 12 | ||
| Mon, Sep 28 | 35–55 | 7.6 | ||
| Tue, Sep 29 | 42–68 | 18 | ||
| Wed, Sep 30 | 56–67 | 12 |
Common questions about the air in Chicago
Is the air in Chicago safe today?
Yes. Right now the US AQI in Chicago is 44, which counts as good. Great air. A perfect time to be outside. It is expected to reach 56 (moderate) around Sun 11:00 AM.
When is the best time to be outside in Chicago?
Sun 1:00 AM–4:00 AM. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 35. The worst hour is around Sun 11:00 AM, at 56.
What is the main pollutant in Chicago?
Fine particles (PM2.5). It drives the index right now, at 7.9 µg/m³. Tiny particles from combustion, fires and dust that reach deep into the lungs. The main driver of AQI worldwide.
How does Chicago's air compare with the WHO guideline?
Within the guideline. Over the next 24 hours PM2.5 averages about 12 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. NO2 is forecast above its guideline level.
How many cigarettes is a day of Chicago's air?
About 0.6 cigarettes. Over the next 24 hours PM2.5 averages about 12 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.
Will air quality in Chicago improve this week?
Today looks cleanest. Its AQI peaks at 46, against 68 on Tuesday, the worst day in the forecast.
Measured near Chicago
| Station | PM2.5 µg/m³ | Measured |
|---|---|---|
| CHI_SP AirNow, reference monitor | 3.5 | Sat 6:00 PM |
| Cicero Liberty AirNow, reference monitor | 4.6 | Sat 6:00 PM |
| CICERO AirNow, reference monitor | – | Sat 6:00 PM |
Air quality near Chicago
- Detroit 381 km E
- Minneapolis 571 km NW
- Toronto 701 km E
- Atlanta 948 km S
- Washington, D.C. 955 km E
- Ottawa 1,036 km NE
About this forecast
Forecast from CAMS global via Open-Meteo: the Copernicus Atmosphere Monitoring Service (CAMS) model at about 40 km resolution (10 km inside Europe), refreshed twice a day. Models smooth out street-level peaks, so busy roads and industrial sites can be worse than shown; ground stations, where there are any nearby, show what monitors actually measure. The US AQI follows the US EPA scale and the European AQI the EEA bands. Readings for 41.88°N, 87.63°W, updated 2026-09-27 00:00 UTC.