Environmental Health & Safety

Air Quality Monitoring

Air Quality

The air quality index, or AQI, is a calculation based on a given air pollutant and its concentration over a period of time. Considered pollutants include ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide; AQI is calculated from the highest pollutant concentration. The index ranges from 0 to 500 with bands for: good, moderate, unhealthy for sensitive groups, unhealthy, very unhealthy, and hazardous.

Color: Green, Level of concern: Good, AQI values: 0 to 50, Description of Air Quality: Air quality is satisfactory, and air pollution poses little to no risk. Color: Yellow, Level of concern: Moderate, AQI values: 51 to 100, Description of Air Quality: Aire quality is acceptable; there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Color: Orange, Level of concern: Unhealthy for sensitive groups, AQI values: 101 to 150, Description of Air Quality: Members of sensitive groups may experience health effects; the general public is less likely to be affected. Color: Red, Level of concern: Unhealthy, AQI values: 151 to 200, Description of Air Quality: Some members of the general public may experience heath effects; sensitive groups may experience more serious health effects. Color: Purple, Level of concern: Very unhealthy, AQI values: 201 to 300, Description of Air Quality: Health alert - risk of health effects is increased for everyone. Color: Maroon, Level of concern: Hazardous, AQI values: 301 and higher, Description of Air Quality: Health warning of emergency conditions: everyone is likely to be affected.

Monitoring Resources

AirNow

The EPA maintains a network of calibrated air monitoring stations across the country, including Santa Cruz County. Official air quality ratings and information can be found on their website, www.airnow.gov

Fire and Smoke Map

A dynamic map detailing regional fire activities and smoke impacts is available through the AirNow site. Santa Cruz area map.

Clarity

Additional air monitoring devices have been installed on campus utilizing equipment from Clarity. Current air quality readings can be located on their interactive map, https://openmap.clarity.io/

 

Campus Actions Depending on AQI

During the 2019 wildfire season air quality at several UC campuses reached concerning levels and prompted a number of activities to be modified or canceled. These action points have been unified into a systemwide decision matrix.

Last modified: Sep 15, 2025