Lake County, Illinois
AQI 40 · Good40
Median AQI
67
90th Percentile
108
Max AQI
200
Days with Data
Ranked #6 of 23 counties in Illinois (by median AQI, lower is better)
Monthly Median AQI — 2025
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40
Median AQI
67
90th Percentile
108
Max AQI
200
Days with Data
Ranked #6 of 23 counties in Illinois (by median AQI, lower is better)
Click a bar to view that month's details