Table 2.

Air Quality Index (AQI) in the U.S.A.

AQI values	Levels of health concerns	Color
0–50	Good	Green
51–100	Moderate	Yellow
101–150	Unhealthy for sensitive groups	Orange
151–200	Unhealthy	Red
201–300	Very Unhealthy	Purple
301–500	Hazardous	Maroon