Inversion

We set off on the sunset side of Tortugas Mountain this morning, reveling in the early morning light, the shadows throwing everything into sharp relief. Here's an example from the trail that skirts the mountain flank.
Looking south to the Franklin Mountains in El Paso, you can see the heavy layer of smog at the base of the mountains. This is the result of a temperature inversion, an atmospheric lid that keeps the pollution from dissipating.

Up here in southern New Mexico, though, the air seemed pretty clear.