Air Quality Index

The Air Quality Index

The Air Quality Index describes air quality and associated health effects. The higher the number, the more air pollution we are breathing. A number of 100 corresponds to the federal health standard for that pollutant. The table below shows numbers and corresponding health statements, focusing on effects you may experience within a few hours or days after breathing polluted air.

Air Quality Index Levels of Health Concern	Numerical Value	What it Means
Good	0-50	Air quality is considered satisfactory, and air pollution poses little or no risk.
Moderate	51-100	Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
Unhealthy for Sensitive Groups	101-150	Members of sensitive groups may experience health effects. The general public is not likely to be affected.
Unhealthy	151-200	Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.
Very Unhealthy	201-300	Health alert: everyone may experience more serious health effects.
Hazardous	> 300	Health warnings of emergency conditions. The entire population is more likely to be affected.

Two types of pollution are of special concern in Santa Barbara County: ozone, a principal component of smog; and particle pollution, also known as particulate matter (PM). Measurements are taken of particles less than 2.5 microns in diameter (PM2.5), and of particles less than 10 microns in diameter (PM10). Real-time Air Quality Index numbers for ozone, PM2.5 and PM10 are available for our monitoring stations on Today's Air Quality. For previous AQI readings, see Summary by Date.

For more information on air quality standards, pollutants and health effects, see Air Pollutants and Our Health. To access data from each station see our Station Data page.