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
8.28 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
36.89 μg/m³
0
55
155
255
425
605+
25.12 ppb
0
55
71
86
201
201+
0.52 ppb
0
36
76
186
605
1005+
4.24 ppb
0
54
101
361
1250
2050+
0.21 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Decatur, Illinois
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AQI 38
Good
7.47μg/m³
PM2.5
31.83μg/m³
PM10
31.05ppb
O3
0.60ppb
SO2
4.13ppb
NO2
0.21ppm
CO
AQI 38
Good
6.97μg/m³
PM2.5
36.19μg/m³
PM10
31.19ppb
O3
0.68ppb
SO2
4.61ppb
NO2
0.21ppm
CO
AQI 38
Good
6.70μg/m³
PM2.5
30.02μg/m³
PM10
33.99ppb
O3
0.79ppb
SO2
4.15ppb
NO2
0.21ppm
CO
AQI 33
Good
5.57μg/m³
PM2.5
26.18μg/m³
PM10
33.20ppb
O3
0.51ppb
SO2
3.02ppb
NO2
0.22ppm
CO
AQI 38
Good
6.94μg/m³
PM2.5
36.63μg/m³
PM10
31.90ppb
O3
0.45ppb
SO2
2.81ppb
NO2
0.19ppm
CO
AQI 38
Good
7.44μg/m³
PM2.5
32.53μg/m³
PM10
30.91ppb
O3
0.61ppb
SO2
4.16ppb
NO2
0.21ppm
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 07:00:00 on 2026-03-09.
In the last 24 hours, the best air quality in Decatur, Illinois was observed at 10:00:00 on 2026-03-09.
As of now, the AQI in Decatur, Illinois is 44, 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 8.277 μg/m3.
The PM10 concentration in Decatur, Illinois is 36.894 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Decatur, Illinois is 0.213 ppm.
Currently, Decatur, Illinois has a sulfur dioxide (SO2) concentration of 0.524 ppb.
The current ozone (O3) level in Decatur, Illinois at the moment is 25.118 ppm.
Nitrogen dioxide (NO2) level in Decatur, Illinois at the moment is 4.244 ppb.
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