Stay updated with real-time air quality in O'Fallon, Illinois featuring accurate data on AQI, PM2.5, PM10, O3, NO2, SO2, and CO levels. Use our interactive map and detailed forecasts to monitor pollution trends, manage health risks, and plan your daily activities with confidence.
Live AQI (Air Quality Index)
50
Good
O'Fallon, Illinois
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
8.93 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
54.32 μg/m³
0
55
155
255
425
605+
9.45 ppb
0
55
71
86
201
201+
0.87 ppb
0
36
76
186
605
1005+
33.39 ppb
0
54
101
361
1250
2050+
0.51 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
O'Fallon, Illinois
O'Fallon, Illinois
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AQI 50
Good
8.93μg/m³
PM2.5
54.32μg/m³
PM10
9.45ppb
O3
0.87ppb
SO2
33.39ppb
NO2
0.51ppm
CO
AQI 50
Good
8.93μg/m³
PM2.5
54.32μg/m³
PM10
9.45ppb
O3
0.87ppb
SO2
33.39ppb
NO2
0.51ppm
CO
AQI 49
Good
8.98μg/m³
PM2.5
49.74μg/m³
PM10
9.65ppb
O3
0.84ppb
SO2
34.47ppb
NO2
0.53ppm
CO
AQI 49
Good
8.89μg/m³
PM2.5
35.40μg/m³
PM10
9.60ppb
O3
0.94ppb
SO2
33.87ppb
NO2
0.53ppm
CO
AQI 49
Good
9.32μg/m³
PM2.5
36.49μg/m³
PM10
9.71ppb
O3
1.00ppb
SO2
32.48ppb
NO2
0.51ppm
CO
AQI 49
Good
8.70μg/m³
PM2.5
30.95μg/m³
PM10
10.41ppb
O3
0.83ppb
SO2
33.93ppb
NO2
0.53ppm
CO
Air quality data and pollutant measurements for Illinois, USA adhere to strict US EPA standards. The data is collected from multiple reliable sources, including satellites and ground-based monitoring stations. This data is further analyzed and enhanced using machine learning and advanced algorithms that factor in elements such as traffic and population density, ensuring accurate and reliable results.
Source: Ambee Data Sources
The air quality for O'fallon, Illinois is updated every hour.
The worst air quality in O'fallon, Illinois in the last 24 hours was observed at 04:00:00 on 2026-01-23.
In the last 24 hrs, the best air quality in O'fallon, Illinois was observed at 01:00:00 on 2026-01-22.
The current air quality in O'fallon, Illinois is 50, categorized as Good based on real-time data.
The most common pollutant in O'fallon, Illinois is PM10.
If the air quality in O'fallon, Illinois is poor, consider staying indoors and wearing a mask to protect yourself.
The current PM2.5 concentration at O'fallon, Illinois is 8.926 μg/m3.
The current PM10 concentration at O'fallon, Illinois is 54.321 μg/m3.
The current carbon monoxide (CO) concentration at O'fallon, Illinois is 0.509 ppm.
The current sulfur dioxide (SO2) concentration at O'fallon, Illinois is 0.869 ppb.
The current ozone (O3) concentration at O'fallon, Illinois is 9.453 ppm.
The current nitrogen dioxide (NO2) concentration at O'fallon, Illinois is 33.391 ppb.
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