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)
26
Good
Decatur, Illinois
Last updated: ... (Local time)
Good
Fine
Moderate
Poor
Very poor
Hazardous
2.59 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
10.55 μg/m³
0
55
155
255
425
605+
27.53 ppb
0
55
71
86
201
201+
0.25 ppb
0
36
76
186
605
1005+
3.77 ppb
0
54
101
361
1250
2050+
0.16 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Decatur, Illinois
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AQI 27
Good
5.48μg/m³
PM2.5
27.56μg/m³
PM10
21.63ppb
O3
0.78ppb
SO2
4.25ppb
NO2
0.16ppm
CO
AQI 33
Good
6.41μg/m³
PM2.5
15.76μg/m³
PM10
16.58ppb
O3
0.77ppb
SO2
5.12ppb
NO2
0.16ppm
CO
AQI 22
Good
4.11μg/m³
PM2.5
18.03μg/m³
PM10
16.01ppb
O3
0.74ppb
SO2
3.61ppb
NO2
0.16ppm
CO
AQI 27
Good
4.53μg/m³
PM2.5
22.42μg/m³
PM10
15.15ppb
O3
0.83ppb
SO2
6.57ppb
NO2
0.13ppm
CO
AQI 27
Good
4.95μg/m³
PM2.5
26.83μg/m³
PM10
21.45ppb
O3
0.76ppb
SO2
4.60ppb
NO2
0.16ppm
CO
AQI 27
Good
5.18μg/m³
PM2.5
24.18μg/m³
PM10
21.81ppb
O3
0.74ppb
SO2
3.48ppb
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 03:00:00 on 2025-07-16.
In the last 24 hours, the best air quality in Decatur, Illinois was observed at 06:00:00 on 2025-07-17.
As of now, the AQI in Decatur, Illinois is 26, indicating Good conditions.
Decatur, Illinois air has the highest levels of O3.
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 2.587 μg/m3.
The PM10 concentration in Decatur, Illinois is 10.548 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 0.252 ppb.
The current ozone (O3) level in Decatur, Illinois at the moment is 27.53 ppm.
Nitrogen dioxide (NO2) level in Decatur, Illinois at the moment is 3.766 ppb.
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