Stay updated with real-time air quality in St. Charles, 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)
49
Good
St. Charles, Missouri
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
9.21 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
34.52 μg/m³
0
55
155
255
425
605+
26.08 ppb
0
55
71
86
201
201+
0.90 ppb
0
36
76
186
605
1005+
5.66 ppb
0
54
101
361
1250
2050+
0.23 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
St. Charles, Missouri
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AQI 52
Moderate
9.93μg/m³
PM2.5
52.21μg/m³
PM10
29.07ppb
O3
0.95ppb
SO2
5.78ppb
NO2
0.26ppm
CO
AQI 52
Moderate
9.93μg/m³
PM2.5
52.91μg/m³
PM10
28.69ppb
O3
0.97ppb
SO2
5.45ppb
NO2
0.26ppm
CO
AQI 52
Moderate
10.12μg/m³
PM2.5
47.81μg/m³
PM10
29.00ppb
O3
1.03ppb
SO2
5.26ppb
NO2
0.26ppm
CO
AQI 52
Moderate
9.79μg/m³
PM2.5
48.92μg/m³
PM10
28.82ppb
O3
1.03ppb
SO2
5.42ppb
NO2
0.27ppm
CO
AQI 52
Moderate
10.03μg/m³
PM2.5
49.63μg/m³
PM10
31.23ppb
O3
1.20ppb
SO2
3.94ppb
NO2
0.26ppm
CO
AQI 52
Moderate
10.37μg/m³
PM2.5
39.99μg/m³
PM10
28.02ppb
O3
1.13ppb
SO2
4.84ppb
NO2
0.26ppm
CO
The air quality data for Missouri, USA is gathered from reliable sources such as satellites and monitoring stations, adhering to US EPA guidelines. With the help of advanced algorithms and machine learning, factors like traffic and population density are analyzed to deliver accurate and dependable results.
Source: Ambee Data Sources
Air quality updates for St. Charles, Missouri are available every hour.
St. Charles, Missouri experienced its worst air quality at 11:00:00, 2026-03-09.
The best air quality in St. Charles, Missouri was observed at 12:00:00 on 2026-03-09.
The air quality in St. Charles, Missouri right now is Moderate, with an AQI of 52.
In St. Charles, Missouri, PM2.5 is the most frequently found pollutant.
When air quality in St. Charles, Missouri is compromised, staying indoors and wearing a mask can reduce health risks.
St. Charles, Missouri currently has a PM2.5 concentration of 9.585 μg/m3.
St. Charles, Missouri currently has a PM10 concentration of 40.734 μg/m3.
The current carbon monoxide (CO) level in St. Charles, Missouri is 0.261 ppm.
The current sulfur dioxide (SO2) concentration in St. Charles, Missouri is 0.918 ppb.
St. Charles, Missouri currently has an ozone (O3) concentration of 27.619 ppm.
The current level of nitrogen dioxide (NO2) in St. Charles, Missouri is 5.782 ppb.
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