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)
22
Good
McHenry, Illinois
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
3.70 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
16.76 μg/m³
0
55
155
255
425
605+
20.00 ppb
0
55
71
86
201
201+
0.33 ppb
0
36
76
186
605
1005+
6.72 ppb
0
54
101
361
1250
2050+
0.20 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
McHenry, Illinois
McHenry, Illinois
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AQI 22
Good
3.70μg/m³
PM2.5
16.76μg/m³
PM10
20.00ppb
O3
0.33ppb
SO2
6.72ppb
NO2
0.20ppm
CO
AQI 22
Good
3.70μg/m³
PM2.5
15.82μg/m³
PM10
19.96ppb
O3
0.34ppb
SO2
6.51ppb
NO2
0.21ppm
CO
AQI 16
Good
3.30μg/m³
PM2.5
14.86μg/m³
PM10
16.94ppb
O3
0.34ppb
SO2
6.24ppb
NO2
0.20ppm
CO
AQI 19
Good
3.11μg/m³
PM2.5
11.91μg/m³
PM10
19.50ppb
O3
0.35ppb
SO2
7.54ppb
NO2
0.21ppm
CO
AQI 16
Good
3.30μg/m³
PM2.5
15.00μg/m³
PM10
17.00ppb
O3
0.34ppb
SO2
5.75ppb
NO2
0.20ppm
CO
AQI 19
Good
3.17μg/m³
PM2.5
13.73μg/m³
PM10
19.98ppb
O3
0.34ppb
SO2
6.29ppb
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 12:00:00 on 2026-06-15.
In the last 24 hrs, the best air quality in Mchenry, Illinois was observed at 06:00:00 on 2026-06-15.
The current air quality in Mchenry, Illinois is 22, 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 3.699 μg/m3.
The current PM10 concentration at Mchenry, Illinois is 16.76 μg/m3.
The current carbon monoxide (CO) concentration at Mchenry, Illinois is 0.205 ppm.
The current sulfur dioxide (SO2) concentration at Mchenry, Illinois is 0.333 ppb.
The current ozone (O3) concentration at Mchenry, Illinois is 19.999 ppm.
The current nitrogen dioxide (NO2) concentration at Mchenry, Illinois is 6.725 ppb.
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