Outdoor
Current values look suitable for ordinary outdoor activity for most people.
Why: Low AQI and low pollutant levels support this guidance.
Chicago, Illinois, United States
Chicago air quality today
Current values look suitable for ordinary outdoor activity for most people.
Data: Hourly Open-Meteo model estimateThe latest update is older than expected, so this page is showing an estimate for the current hour.Detailed metrics and guidance use the latest available detailed data.
Practical guidance
Running
Current values look suitable for an easy outdoor run.
Why: Low AQI and low pollutant levels support this guidance.
Ventilation
Consider waiting before longer ventilation.
Why: PM2.5, PM10, NO2 or ozone is elevated, so longer ventilation may bring more outdoor pollution indoors.
Air quality and outdoor metrics
US AQI
Air Quality Index
34
Good
PM2.5
Fine particulate matter
10.2µg/m³
Moderate
PM10
Coarse particulate matter
10.4µg/m³
Low
NO₂
Nitrogen dioxide
26µg/m³
Low
O₃
Ozone
43µg/m³
Low
UV index
Sun exposure level
1
Low
Temperature
Air temperature
15°C
Comfortable
Feels like
Apparent temperature
13°C
Comfortable
Wind
Wind speed
10km/h
Light
Humidity
Relative humidity
56%
Comfortable
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Disclaimer
This information is a general estimate only and is not medical advice.
Location
Chicago, United States
Coordinates: 41.8781, -87.6298 · America/Chicago
Interpret AQI for outdoor activity
Calculic's European AQI calculator assesses the value using your population group and planned activity intensity.
Interpret AQI in CalculicThis page's European AQI value, city and timestamp are passed to the calculator through the link.
What affects air quality in Chicago
Illinois EPA reports that direct PM2.5 emissions in the Chicago Study Area are highest in Cook and Will Counties, with nonpoint area sources the largest contributor.
This is a regional emissions-inventory comparison, not a current citywide Chicago reading or a statement that sources are uniform across the study area.
Local monitoring and context
Illinois EPA's 2026 network plan lists multiple Cook County monitors in Chicago, including Kennedy Near-road, Mayfair Pump Station, Perez Elementary School and South Water Filtration Plant.
The named sites have distinct objectives and pollutant coverage; none is presented as a single citywide Chicago reading or this page's current source.
City air quality FAQ
How should I read the AQI for Chicago?
US AQI condenses air quality into one value. On this page, it helps you quickly judge whether conditions look good, moderate or more polluted than usual.
Is the air quality good for going outside?
Check the outdoor and running cards first. They combine AQI, particles, ozone, weather and other factors that can affect outdoor comfort.
Should I ventilate right now?
The ventilation card considers AQI and pollutants such as particles, nitrogen dioxide and ozone. If values are elevated, a shorter opening or a later moment may be better.
Why can air quality change during the day?
Weather, emissions, ozone formation, particles and air flow can shift local conditions, so the next hours can differ from the current reading.
Sources and methodology
Current data
This page uses US AQI.
Current and hourly air-quality values are CAMS-based model estimates, not measurements from a local monitoring station. They may not reflect street-level conditions.
- Displayed state
- This hour's model estimate
- Data time
- 31 Oct 2026, 12:00 pm
- Weather data
- Open-Meteo
- Air-quality model data
- Copernicus Atmosphere Monitoring Service (CAMS). Open-Meteo selects data suited to this location. Possible CAMS datasets: CAMS European air quality forecasts, ENSEMBLE data; CAMS global atmospheric composition forecasts.
- Licence
- CC BY 4.0
City Air Quality selects the active data package, combines weather and air-quality data, chooses the current or latest usable model value, and formats it for this page.
The latest update is older than expected, so this page is showing an estimate for the current hour.
Detailed metrics and guidance use the latest available detailed data.
Evergreen city statements
Each local statement is linked to a checked primary-authority source. A source check is editorial provenance and does not describe current-data freshness.
Local sources support the background claims below; they are not the source of the current data shown above unless explicitly stated otherwise.
Authoritative sources for local statements
Illinois Recommended Designations for the 2024 Annual PM2.5 Standard
Illinois Environmental Protection Agency
- Scope
- Chicago Study Area
- Source checked
- 22 Aug 2026
Page 22 compares direct PM2.5 emissions by county and identifies nonpoint area sources as the greatest contributor in Cook and Will Counties.
Applicability: Chicago Study Area emissions analysis; county totals and source categories do not represent current uniform conditions within Chicago.
Based on this source: Illinois EPA reports that direct PM2.5 emissions in the Chicago Study Area are highest in Cook and Will Counties, with nonpoint area sources the largest contributor.
2026 Ambient Air Monitoring Network Plan
Illinois Environmental Protection Agency
- Scope
- Chicago
- Source checked
- 22 Aug 2026
PDF file page 15 of 45 (printed page 13), Table 1: Illinois Monitoring Network by Criteria Pollutant, lists South Water Filtration Plant, Mayfair Pump Station, Perez Elementary School and Kennedy Near-road #2 in Chicago with address, site-description and owner metadata.
Applicability: Chicago site directory in the statewide plan; each listed monitor has its own location, scale and purpose.
Based on this source: Illinois EPA's 2026 network plan lists multiple Cook County monitors in Chicago, including Kennedy Near-road, Mayfair Pump Station, Perez Elementary School and South Water Filtration Plant.