Stay updated with real-time air quality in McHenry, 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
McHenry, Illinois
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
6.01 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
21.52 μg/m³
0
55
155
255
425
605+
21.39 ppb
0
55
71
86
201
201+
2.05 ppb
0
36
76
186
605
1005+
9.70 ppb
0
54
101
361
1250
2050+
0.19 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
McHenry, Illinois
McHenry, Illinois
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AQI 33
Good
6.19μg/m³
PM2.5
18.29μg/m³
PM10
23.37ppb
O3
1.24ppb
SO2
10.45ppb
NO2
0.20ppm
CO
AQI 33
Good
6.46μg/m³
PM2.5
18.24μg/m³
PM10
22.99ppb
O3
1.24ppb
SO2
10.47ppb
NO2
0.21ppm
CO
AQI 27
Good
5.03μg/m³
PM2.5
21.58μg/m³
PM10
22.92ppb
O3
1.27ppb
SO2
12.45ppb
NO2
0.20ppm
CO
AQI 38
Good
6.68μg/m³
PM2.5
23.50μg/m³
PM10
23.31ppb
O3
1.28ppb
SO2
15.69ppb
NO2
0.21ppm
CO
AQI 27
Good
4.90μg/m³
PM2.5
21.00μg/m³
PM10
23.01ppb
O3
1.26ppb
SO2
11.58ppb
NO2
0.20ppm
CO
AQI 33
Good
6.40μg/m³
PM2.5
24.10μg/m³
PM10
23.02ppb
O3
1.24ppb
SO2
10.48ppb
NO2
0.21ppm
CO
Air quality data and pollutant measurements for Illinois, USA adhere to strict US EPA standards. The data is collected from multiple reliable sources, including satellites and ground-based monitoring stations. This data is further analyzed and enhanced using machine learning and advanced algorithms that factor in elements such as traffic and population density, ensuring accurate and reliable results.
Source: Ambee Data Sources
The air quality for Mchenry, Illinois is updated every hour.
The worst air quality in Mchenry, Illinois in the last 24 hours was observed at 05:00:00 on 2026-01-25.
In the last 24 hrs, the best air quality in Mchenry, Illinois was observed at 02:00:00 on 2026-01-25.
The current air quality in Mchenry, Illinois is 33, categorized as Good based on real-time data.
The most common pollutant in Mchenry, Illinois is PM2.5.
If the air quality in Mchenry, Illinois is poor, consider staying indoors and wearing a mask to protect yourself.
The current PM2.5 concentration at Mchenry, Illinois is 6.013 μg/m3.
The current PM10 concentration at Mchenry, Illinois is 21.523 μg/m3.
The current carbon monoxide (CO) concentration at Mchenry, Illinois is 0.191 ppm.
The current sulfur dioxide (SO2) concentration at Mchenry, Illinois is 2.048 ppb.
The current ozone (O3) concentration at Mchenry, Illinois is 21.395 ppm.
The current nitrogen dioxide (NO2) concentration at Mchenry, Illinois is 9.701 ppb.
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