Stay updated with real-time air quality in Decatur, 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)
44
Good
Decatur, Illinois
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
8.26 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
36.83 μg/m³
0
55
155
255
425
605+
19.08 ppb
0
55
71
86
201
201+
0.72 ppb
0
36
76
186
605
1005+
24.92 ppb
0
54
101
361
1250
2050+
0.39 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Decatur, Illinois
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AQI 33
Good
6.39μg/m³
PM2.5
27.60μg/m³
PM10
19.12ppb
O3
0.63ppb
SO2
17.58ppb
NO2
0.27ppm
CO
AQI 33
Good
6.43μg/m³
PM2.5
27.70μg/m³
PM10
20.19ppb
O3
0.37ppb
SO2
22.57ppb
NO2
0.25ppm
CO
AQI 38
Good
6.60μg/m³
PM2.5
29.98μg/m³
PM10
22.00ppb
O3
0.50ppb
SO2
22.85ppb
NO2
0.28ppm
CO
AQI 33
Good
6.09μg/m³
PM2.5
29.45μg/m³
PM10
11.40ppb
O3
0.25ppb
SO2
19.07ppb
NO2
0.19ppm
CO
AQI 27
Good
5.13μg/m³
PM2.5
19.53μg/m³
PM10
10.49ppb
O3
0.64ppb
SO2
21.28ppb
NO2
0.30ppm
CO
AQI 33
Good
6.40μg/m³
PM2.5
25.19μg/m³
PM10
26.19ppb
O3
0.70ppb
SO2
17.40ppb
NO2
0.29ppm
CO
Air quality and pollutant data for Illinois, USA are sourced from ground-based monitors and satellites, adhering to US EPA standards. Machine learning and advanced algorithms enhance the data by incorporating local variables like traffic and population density, ensuring high accuracy and dependability.
Source: Ambee Data Sources
The air quality information for Decatur, Illinois is updated every hour for accuracy.
In the past 24 hours, the air quality in Decatur, Illinois was at its worst at 02:00:00 on 2026-10-09.
In the last 24 hours, the best air quality in Decatur, Illinois was observed at 07:00:00 on 2026-10-08.
As of now, the AQI in Decatur, Illinois is 38, indicating Good conditions.
Decatur, Illinois air has the highest levels of PM2.5.
Poor air quality in Decatur, Illinois means it's advisable to stay indoors and wear a mask for your protection.
PM2.5 levels in Decatur, Illinois are currently 7.374 μg/m3.
The PM10 concentration in Decatur, Illinois is 32.879 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Decatur, Illinois is 0.221 ppm.
Currently, Decatur, Illinois has a sulfur dioxide (SO2) concentration of 0.512 ppb.
The current ozone (O3) level in Decatur, Illinois at the moment is 20.945 ppm.
Nitrogen dioxide (NO2) level in Decatur, Illinois at the moment is 21.938 ppb.
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