Cook, Illinois Air Quality

Cook County, Illinois (IL)

→ Stableover 10 years

Air Quality Grade

49/100

Current Median AQI

Moderate

5-Year Avg AQI

-2

10-Year Change

Better

Unhealthy Days/yr

5-year average

PM2.5

Primary Pollutant

Fine Particulate Matter (PM2.5)

10-Year AQI Trend

The solid line shows the median AQI each year. The dashed line shows the 90th percentile (worst 10% of days).

Air Quality Day Breakdown

Number of days per year in each EPA AQI category. Green = Good (AQI 0-50), Yellow = Moderate (51-100), Orange = Unhealthy for Sensitive Groups (101-150), Red = Unhealthy or worse (151+).

Year-by-Year Data

Year	Median AQI	90th Pct	Max AQI	Good Days	Moderate	Unhealthy+	Pollutant
2023	57	93	223	104	227	34	PM2.5
2022	54	76	151	117	240	8	PM2.5
2021	59	89	156	87	257	21	PM2.5
2020	58	84	164	86	260	20	PM2.5
2019	58	79	133	80	276	9	PM2.5
2018	59	86	177	86	260	19	PM2.5
2017	55	87	177	114	232	19	PM2.5
2016	56	80	169	115	233	18	PM2.5
2015	57	79	195	73	285	7	PM2.5
2014	59	80	143	76	281	8	PM2.5

What This Means for Cook County Residents

Cook, Illinois has received an Air Quality Grade of D (49/100) based on a decade of EPA monitoring data. The current median AQI of 57 falls in the "Moderate" range.

The primary pollutant affecting this area is Fine Particulate Matter (PM2.5). Over the past 5 years, this area has averaged 18 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.