Boulder County residents who are concerned about breathing pollutants from the Marshall fire can now check air quality on an interactive map guided by 25 state-of-the-art air monitors placed throughout the burn area. 

The map shows how good or bad the air is in real time and suggests whether it’s a good idea to go outside, according to Boulder County Public Health.

The results are in accordance with the Environmental Protection Agency’s U.S. Air Quality Index, which uses a number from 0 to 500, with the numbers increasing according to how bad the air is. 

A value of 50 or below is considered good air quality, a value above 100 means air quality is unhealthy, and a value over 300 indicates hazardous air quality. As of Monday, all 25 monitors were showing good air quality near where the fire started. The air quality ranged from a concentration of 13 to the highest reading at Southern Hills Middle School, showing a 15, both of which are in the “good range” for the EPA’s measurements.

People in the Marshall fire area should have their air ducts cleaned and watch for any soot or ash clinging to their shoes when they enter their homes, according to Boulder County Public Health.