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)
22
Good
Decatur, Illinois
Last updated: ... (Local time)
Good
Fine
Moderate
Poor
Very poor
Hazardous
4.13 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
18.15 μg/m³
0
55
155
255
425
605+
14.09 ppb
0
55
71
86
201
201+
0.78 ppb
0
36
76
186
605
1005+
8.83 ppb
0
54
101
361
1250
2050+
0.20 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Decatur, Illinois
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AQI 49
Good
8.98μg/m³
PM2.5
32.12μg/m³
PM10
27.41ppb
O3
0.88ppb
SO2
2.38ppb
NO2
0.16ppm
CO
AQI 26
Good
4.42μg/m³
PM2.5
12.99μg/m³
PM10
27.71ppb
O3
0.84ppb
SO2
2.38ppb
NO2
0.15ppm
CO
AQI 44
Good
7.81μg/m³
PM2.5
34.01μg/m³
PM10
21.02ppb
O3
0.86ppb
SO2
2.40ppb
NO2
0.16ppm
CO
AQI 27
Good
3.89μg/m³
PM2.5
25.89μg/m³
PM10
28.98ppb
O3
0.91ppb
SO2
2.94ppb
NO2
0.16ppm
CO
AQI 56
Moderate
11.59μg/m³
PM2.5
45.52μg/m³
PM10
26.99ppb
O3
0.86ppb
SO2
2.39ppb
NO2
0.23ppm
CO
AQI 38
Good
6.94μg/m³
PM2.5
36.62μg/m³
PM10
24.38ppb
O3
0.87ppb
SO2
2.40ppb
NO2
0.16ppm
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 08:00:00 on 2025-07-19.
In the last 24 hours, the best air quality in Decatur, Illinois was observed at 05:00:00 on 2025-07-20.
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 7.216 μg/m3.
The PM10 concentration in Decatur, Illinois is 31.874 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Decatur, Illinois is 0.159 ppm.
Currently, Decatur, Illinois has a sulfur dioxide (SO2) concentration of 0.468 ppb.
The current ozone (O3) level in Decatur, Illinois at the moment is 36.1 ppm.
Nitrogen dioxide (NO2) level in Decatur, Illinois at the moment is 0.929 ppb.
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