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)
33
Good
Decatur, Illinois
Last updated: ... (Local time)
Good
Fine
Moderate
Poor
Very poor
Hazardous
6.38 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
28.92 μg/m³
0
55
155
255
425
605+
24.97 ppb
0
55
71
86
201
201+
1.03 ppb
0
36
76
186
605
1005+
1.58 ppb
0
54
101
361
1250
2050+
0.17 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Decatur, Illinois
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AQI 40
Good
6.10μg/m³
PM2.5
43.12μg/m³
PM10
29.59ppb
O3
0.72ppb
SO2
2.51ppb
NO2
0.17ppm
CO
AQI 33
Good
5.67μg/m³
PM2.5
31.97μg/m³
PM10
28.64ppb
O3
0.68ppb
SO2
2.38ppb
NO2
0.18ppm
CO
AQI 33
Good
6.30μg/m³
PM2.5
27.99μg/m³
PM10
27.01ppb
O3
0.51ppb
SO2
2.44ppb
NO2
0.17ppm
CO
AQI 33
Good
5.68μg/m³
PM2.5
34.82μg/m³
PM10
23.80ppb
O3
1.06ppb
SO2
2.66ppb
NO2
0.14ppm
CO
AQI 44
Good
5.88μg/m³
PM2.5
46.51μg/m³
PM10
25.37ppb
O3
0.92ppb
SO2
3.55ppb
NO2
0.19ppm
CO
AQI 38
Good
7.34μg/m³
PM2.5
26.78μg/m³
PM10
29.32ppb
O3
0.61ppb
SO2
2.47ppb
NO2
0.18ppm
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 11:00:00 on 2025-09-04.
In the last 24 hours, the best air quality in Decatur, Illinois was observed at 09:00:00 on 2025-09-05.
As of now, the AQI in Decatur, Illinois is 33, 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 5.691 μg/m3.
The PM10 concentration in Decatur, Illinois is 24.964 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Decatur, Illinois is 0.145 ppm.
Currently, Decatur, Illinois has a sulfur dioxide (SO2) concentration of 0.882 ppb.
The current ozone (O3) level in Decatur, Illinois at the moment is 27.982 ppm.
Nitrogen dioxide (NO2) level in Decatur, Illinois at the moment is 3.44 ppb.
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