Air Quality Index (AQI)

AQI Standard

In USA, we use EPA 454/B-18-007.

In China, we use HJ633-2012.

AQI Description

The natural language descriptions for air quality conform to the 5 levels, with a possible seventh for missing data:

0: "missing"
1: "good"
2: "satisfactory"
3: "moderate"
4: "unhealthy"
5: "very poor"
6: "hazardous"