Is the air in Chicago safe today?

Yes. Right now the US AQI in Chicago is 32, which counts as good. Great air. A perfect time to be outside.

When is the best time to be outside in Chicago?

Sat 6:00 AM–9:00 AM. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 21. The worst hour is around Fri 12:00 PM, at 33.

What is the main pollutant in Chicago?

Ozone (O3). It drives the index right now, at 69 µg/m³. Formed by sunlight acting on traffic and plant emissions. Highest on hot, still afternoons, often downwind of cities.

How does Chicago's air compare with the WHO guideline?

Within the guideline. Over the next 24 hours PM2.5 averages about 1.6 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. The other pollutants stay within their guideline levels.

How many cigarettes is a day of Chicago's air?

Less than a tenth of one. Over the next 24 hours PM2.5 averages about 1.6 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 33, against 99 on Sunday, the worst day in the forecast.

Chicago air quality

Illinois, United States · Live AQI and hourly forecast for the next 5 days · valid Fri 11:00 AM local time

Good

US AQI, mostly O₃

Model estimate. Nearby measurements are shown separately.

Great air. A perfect time to be outside.

Next 24 hours: 21–33US AQI, highest around Fri 12:00 PM
Best time outside: Sat 6:00 AM–9:00 AMUS AQI about 21
PM_2.5 vs WHO guideline: 0.1×1.6 µg/m³ over 24 h, guideline 15
Cigarette equivalent: ≈ 0 a dayBerkeley Earth rule of thumb

Loading the live globe…

The live globe, centred on Chicago. Switch pollutants, drag through the next 5 days or press play. Full map →

Pollutants in Chicago right now

Pollutant	Now	Level	Next 24 h vs WHO
Fine particles PM_2.5	1.1 µg/m³	Good	0.1×
Coarse particles PM₁₀	1.1 µg/m³	Good	0.0×
Nitrogen dioxide NO₂	6.9 µg/m³	Good	0.3×
Ozone O₃	69 µg/m³	Good	0.7×
Sulphur dioxide SO₂	0.7 µg/m³	Good	0.0×
Carbon monoxide CO	126 µg/m³	Good	0.0×
Aerosol optical depth	0.04	Whole atmosphere · dimensionless
Desert dust	0 µg/m³	Modelled surface dust
UV index	1	Low

“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 PM_2.5, 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. Levels follow the US AQI, which is far less strict than the WHO, so air rated Good can still be above a guideline.

Next 48 hours

Hourly US AQI. Highest 56 around Sun 8:00 AM, lowest 21 around Sat 7:00 AM.

Good 0–50Moderate 51–100Sensitive 101–150Unhealthy 151–200Very unhealthy 201–300Hazardous 301+

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	Worst hour	PM_2.5 avg	UV max
Fri, Nov 13	28–33	Good	12:00 AM	1.4	1 Low
Sat, Nov 14	21–55	Moderate	11:00 PM	3.9	2 Low
Sun, Nov 15	32–99	Moderate	10:00 PM	13	2 Low
Mon, Nov 16	53–92	Moderate	12:00 AM	19	2 Low
Tue, Nov 17	55–67	Moderate	8:00 AM	14	2 Low

Common questions about the air in Chicago

Is the air in Chicago safe today?
Yes. Right now the US AQI in Chicago is 32, which counts as good. Great air. A perfect time to be outside.
When is the best time to be outside in Chicago?
Sat 6:00 AM–9:00 AM. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 21. The worst hour is around Fri 12:00 PM, at 33.
What is the main pollutant in Chicago?
Ozone (O₃). It drives the index right now, at 69 µg/m³. Formed by sunlight acting on traffic and plant emissions. Highest on hot, still afternoons, often downwind of cities.
How does Chicago's air compare with the WHO guideline?
Within the guideline. Over the next 24 hours PM_2.5 averages about 1.6 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. The other pollutants stay within their guideline levels.
How many cigarettes is a day of Chicago's air?
Less than a tenth of one. Over the next 24 hours PM_2.5 averages about 1.6 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 33, against 99 on Sunday, the worst day in the forecast.

Measured near Chicago

Station and measurements	Distance	US AQI	Level
Unnamed sensor OpenAQ, low-cost sensor PM_2.5: 3.6 µg/m³ · Fri 11:05 AM	1.0 km	20	Good
Unnamed sensor OpenAQ, low-cost sensor PM_2.5: 4.8 µg/m³ · Fri 11:04 AM	1.3 km	27	Good
Unnamed sensor OpenAQ, low-cost sensor PM_2.5: 3.8 µg/m³ · Fri 11:02 AM	1.4 km	21	Good

Air quality near Chicago

US AQI right now. Cleanest nearby: Detroit (24); worst: Atlanta (33). The tick on each bar is Chicago, at 32.

Detroit 381 km E 24 Good
Minneapolis 571 km NW 29 Good
Toronto 701 km E 30 Good
Atlanta 948 km S 33 Good
Washington, D.C. 955 km E 32 Good
Ottawa 1,036 km NE 30 Good

All 162 cities →

About this forecast

Forecast from CAMS global via Open-Meteo: the Copernicus Atmosphere Monitoring Service (CAMS) model at about 40 km resolution (about 10 km inside Europe). Global runs update every 12 hours and European runs every 24 hours. Models smooth out street-level peaks, so busy roads and industrial sites can be worse than shown. Nearby station measurements are independent observations, not adjustments to the forecast. The point forecast uses Open-Meteo’s CAMS products, including a separate carbon monoxide product; it can differ from the globe’s global grid. The AQI rates each hour on the US EPA scale, the same way the map colors it; official daily figures average over 24 hours (8 for ozone), so they can read lower after a short peak. Readings for 41.88°N, 87.63°W, valid 2026-11-13 17:00 UTC.