The National Oceanic and Atmospheric Administration (NOAA), in partnership with the Environmental Protection Agency (EPA), issues daily air quality forecast guidance as part of a national Air Quality Forecasting Capability. NOAA's National Weather Service (NWS) currently provides forecast guidance for ozone and smoke based on numerical atmospheric predictions updated twice daily.
The EPA developed the Air Quality Index (AQI) which reports levels of ozone, particle pollution, and other common air pollutants on the same scale. An AQI reading of 101 corresponds to a level that is above the national air quality standard - the higher the AQI rating, the greater the health impact. The AQI is divided into color-coded categories, and each category is identified by a simple informative descriptor. The descriptors are intended to convey to the public information about how air quality within each category relates to public health.
The table below defines the AQI categories.
|AQI||AQI Category||AQI||Color Formulas|
|0 - 50||Good||Green||0,228,0||224,0,224,30|
|51 - 100||Moderate||Yellow||255,255,0||0,0,255,0|
|101 - 150||Unhealthy for Sensitive Groups||Orange||255,126,0||0,132,255,0|
|151 - 200||Unhealthy||Red||255,0,0||0,255,255,0|
|201 - 300||Very Unhealthy||Purple||153,0,76||0,153,80,102|
|301 - 500||Hazardous||Maroon||76,0,38||0,76,38,179|