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)
66
Moderate
Decatur, Illinois
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
16.80 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
74.99 μg/m³
0
55
155
255
425
605+
15.21 ppb
0
55
71
86
201
201+
0.78 ppb
0
36
76
186
605
1005+
8.29 ppb
0
54
101
361
1250
2050+
0.18 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Decatur, Illinois
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AQI 66
Moderate
17.02μg/m³
PM2.5
61.89μg/m³
PM10
13.43ppb
O3
0.71ppb
SO2
9.18ppb
NO2
0.21ppm
CO
AQI 66
Moderate
16.96μg/m³
PM2.5
75.07μg/m³
PM10
16.21ppb
O3
0.61ppb
SO2
9.00ppb
NO2
0.20ppm
CO
AQI 60
Moderate
14.22μg/m³
PM2.5
63.10μg/m³
PM10
14.39ppb
O3
0.72ppb
SO2
9.47ppb
NO2
0.21ppm
CO
AQI 66
Moderate
17.48μg/m³
PM2.5
62.18μg/m³
PM10
14.67ppb
O3
0.67ppb
SO2
8.84ppb
NO2
0.13ppm
CO
AQI 60
Moderate
13.92μg/m³
PM2.5
62.44μg/m³
PM10
12.34ppb
O3
0.81ppb
SO2
4.30ppb
NO2
0.22ppm
CO
AQI 66
Moderate
17.44μg/m³
PM2.5
73.03μg/m³
PM10
14.92ppb
O3
0.73ppb
SO2
9.51ppb
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 01:00:00 on 2025-12-07.
In the last 24 hours, the best air quality in Decatur, Illinois was observed at 07:00:00 on 2025-12-06.
As of now, the AQI in Decatur, Illinois is 66, indicating Moderate 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 16.801 μg/m3.
The PM10 concentration in Decatur, Illinois is 74.991 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Decatur, Illinois is 0.177 ppm.
Currently, Decatur, Illinois has a sulfur dioxide (SO2) concentration of 0.779 ppb.
The current ozone (O3) level in Decatur, Illinois at the moment is 15.209 ppm.
Nitrogen dioxide (NO2) level in Decatur, Illinois at the moment is 8.286 ppb.
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