US EPA has developed an Air Quality Index (AQI) (see chart below) to provide easy to understand information on local air quality and whether air pollution levels pose a health concern.
Air Quality Index health rankings are based on 1-hour and 24-hour concentration averages. EPA developed the health indices based on 24-hour averages. Idaho State’s Department of Environmental Quality developed health indices based on 1-hour averages.
AQI Category (AQI Values) |
PM2.5 or PM10 Levels (ug/m3) | Visibility - Arid Conditions (miles) | Recommended Actions | ||
1-3 hr avg | 8 hr avg | 24 hr avg | |||
Good (0-50) |
0 –38 | 0 – 22 | 0 – 12 | >= 11 |
|
Moderate (51 – 100) |
39 – 88 | 23 – 50 | 12.1 – 35.4 | 6 – 10 |
|
Unhealthy for Sensitive Groups (101 - 150) |
89 – 351 | 51 – 79 | 35.5 – 55.4 | 3 – 5 |
|
Unhealthy (151 – 200) |
139 – 351 | 80 – 200 | 55.5 – 150.4 | 1.5 – 2.75 |
|
Very Unhealthy (201 – 300) |
352 – 526 | 201 – 300 | 150.5 – 250.4 | 1 – 1.25 |
|
Hazardous (>300) |
> 526 | > 300 | 250.5 - 500 | < 1 |
|