PITTSBURGH (KDKA) — The Department of Environmental Protection has issued a Code Orange Air Quality Alert for parts of Western Pennsylvania.

An Air Quality Alert has been issued, Thursday, for Allegheny, Armstrong, Beaver, Butler, Fayette, Washington and Westmoreland counties.  These are issued when air pollution concentrations may become unhealthy for those with breathing issues and sensitive groups, like the very young and elderly.

READ MORE: 'Dasher's Light Show' Tickets Now On Sale For This Christmas Season

(Photo Credit: KDKA)

As you go higher into the atmosphere, temperatures usually cool. When you have an inversion, however, temperatures rise as you ascend through the atmosphere.

You can see the inversion on the latest weather balloon “sounding” from Pittsburgh.

(Photo Credit: KDKA)

READ MORE: Take Action Mon Valley Demands Answers After 2 Incidents Involving Police Officers In Homestead

Temperatures are depicted by the red line. When that line moves to the right, warming is indicated. As the line travels higher into the atmosphere, you can clearly see the temperature inversion.

Inversions have been getting a lot of attention in the Pittsburgh area lately.

These inversions play a major role in trapping pollution near the Earth’s surface. Usually, these air pollutants are associated with heat, so they rise higher into the atmosphere. When we have a temperature inversion, that heat can no longer lift the pollutants away.

The impacts from air pollution can be minimized by staying indoors and avoiding strenuous, outdoor activities.

MORE NEWS: Pittsburgh Department Of Public Works Looking For Artist To Help Design New Playground

Stay with KDKA for more on this developing story.