What is the air quality in St. Louis MO IL?

St. Louis MO IL, United States of America has an annual US AQI of 55 (Reasonable) and average PM2.5 of 11.8 µg/m³, ranking #1341 of 5856 cities. Main pollutant: PM2.5.

What is the cleanest month in St. Louis MO IL?

April is typically the cleanest month (AQI 50) and July the most polluted (AQI 61).

Where does St. Louis MO IL's air quality data come from?

PM2.5: 1998–2026 (monitors 1999–2026, satellite 1998; 2026 provisional (AirNow)). Measured by government monitoring stations. Full sources are on the methodology page.

St. Louis MO IL, United States of America — Air Quality & Clean City Guide 2026

St. Louis MO IL Air Quality Data

Global rank	City	Continent	AQI	PM2.5
1341	St. Louis MO IL, United States of America	North America	AQI 55	PM2.5 11.8 µg/m³