Saint Louis County, Missouri
AQI 39 · Good39
Median AQI
51
90th Percentile
93
Max AQI
148
Days with Data
Ranked #5 of 21 counties in Missouri (by median AQI, lower is better)
Monthly Median AQI — 2025
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39
Median AQI
51
90th Percentile
93
Max AQI
148
Days with Data
Ranked #5 of 21 counties in Missouri (by median AQI, lower is better)
Click a bar to view that month's details