The air in Middle Tennessee reached unhealthy levels, prompting a code red in air quality levels.
The Air Quality Index indicated Friday's air as unhealthy. The AQUI value is measured from 0 to 500. Unhealthy levels are between 151 to 200.
At those levels all groups of people are effected. Children, elderly, and those with respiratory issues may experience more serious health effects.
An AQI value of 50 represents good air quality with little potential to affect public health, while an AQI value over 300 represents hazardous air quality.
Below is a graph from Air Now explaining what each quality level means.