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)
27
Good
Decatur, Illinois
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
4.63 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
20.11 μg/m³
0
55
155
255
425
605+
22.06 ppb
0
55
71
86
201
201+
0.85 ppb
0
36
76
186
605
1005+
5.33 ppb
0
54
101
361
1250
2050+
0.14 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Decatur, Illinois
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AQI 38
Good
6.60μg/m³
PM2.5
33.87μg/m³
PM10
26.27ppb
O3
0.52ppb
SO2
8.42ppb
NO2
0.26ppm
CO
AQI 33
Good
6.18μg/m³
PM2.5
24.36μg/m³
PM10
23.35ppb
O3
0.64ppb
SO2
12.45ppb
NO2
0.25ppm
CO
AQI 22
Good
3.14μg/m³
PM2.5
14.17μg/m³
PM10
24.06ppb
O3
0.67ppb
SO2
7.95ppb
NO2
0.26ppm
CO
AQI 38
Good
6.86μg/m³
PM2.5
38.44μg/m³
PM10
20.39ppb
O3
0.44ppb
SO2
10.43ppb
NO2
0.16ppm
CO
AQI 44
Good
7.55μg/m³
PM2.5
33.12μg/m³
PM10
28.11ppb
O3
1.26ppb
SO2
3.27ppb
NO2
0.21ppm
CO
AQI 33
Good
5.74μg/m³
PM2.5
21.78μg/m³
PM10
23.95ppb
O3
0.67ppb
SO2
7.63ppb
NO2
0.26ppm
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 2026-02-12.
In the last 24 hours, the best air quality in Decatur, Illinois was observed at 12:00:00 on 2026-02-12.
As of now, the AQI in Decatur, Illinois is 27, 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 4.625 μg/m3.
The PM10 concentration in Decatur, Illinois is 20.114 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Decatur, Illinois is 0.138 ppm.
Currently, Decatur, Illinois has a sulfur dioxide (SO2) concentration of 0.848 ppb.
The current ozone (O3) level in Decatur, Illinois at the moment is 22.06 ppm.
Nitrogen dioxide (NO2) level in Decatur, Illinois at the moment is 5.329 ppb.
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