Stay updated with real-time air quality in O'Fallon, Missouri 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)
26
Good
O'Fallon, Missouri
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
2.97 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
15.22 μg/m³
0
55
155
255
425
605+
28.24 ppb
0
55
71
86
201
201+
0.94 ppb
0
36
76
186
605
1005+
4.18 ppb
0
54
101
361
1250
2050+
0.14 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
O'Fallon, Missouri
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AQI 27
Good
2.54μg/m³
PM2.5
15.63μg/m³
PM10
28.99ppb
O3
0.70ppb
SO2
3.99ppb
NO2
0.15ppm
CO
AQI 27
Good
2.54μg/m³
PM2.5
15.73μg/m³
PM10
29.00ppb
O3
0.76ppb
SO2
3.76ppb
NO2
0.15ppm
CO
AQI 27
Good
2.70μg/m³
PM2.5
15.49μg/m³
PM10
28.98ppb
O3
0.64ppb
SO2
3.98ppb
NO2
0.15ppm
CO
AQI 27
Good
2.54μg/m³
PM2.5
15.88μg/m³
PM10
29.00ppb
O3
0.80ppb
SO2
3.68ppb
NO2
0.15ppm
CO
AQI 27
Good
2.54μg/m³
PM2.5
15.99μg/m³
PM10
28.99ppb
O3
0.84ppb
SO2
3.66ppb
NO2
0.15ppm
CO
AQI 27
Good
2.67μg/m³
PM2.5
15.08μg/m³
PM10
29.05ppb
O3
0.40ppb
SO2
3.22ppb
NO2
0.16ppm
CO
Air quality measurements for Missouri, USA meet strict US EPA standards. These measurements are collected from reliable sources, including satellites and ground-based monitoring systems. Advanced algorithms and machine learning techniques are applied to the data, factoring in variables such as traffic and population density, to ensure precision and reliability.
Source: Ambee Data Sources
Air quality data for O'fallon, Missouri is updated on an hourly basis.
The worst air quality in O'fallon, Missouri was recorded at 05:00:00 on 2026-01-23.
The best air quality in O'fallon, Missouri was recorded at 04:00:00 on 2026-01-22.
The real-time air quality index in O'fallon, Missouri is 26, currently categorized as Good.
The most common pollutant in O'fallon, Missouri is O3.
If the air quality in O'fallon, Missouri is poor, limit outdoor activities and use a mask to safeguard your health.
The measured PM2.5 levels in O'fallon, Missouri at present are 2.967 μg/m3.
The current PM10 levels in O'fallon, Missouri are 15.223 μg/m3.
The current carbon monoxide (CO) level in O'fallon, Missouri is 0.145 ppm.
The current sulfur dioxide (SO2) levels in O'fallon, Missouri are 0.935 ppb.
The current ozone (O3) levels at O'fallon, Missouri is 28.241 ppm.
The current nitrogen dioxide (NO2) levels at O'fallon, Missouri is 4.183 ppb.
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