I'm attempting to design a desert area that could almost constantly be covered in a thin layer of smoke. It does not block out the sun but instead sticks closer to the ground. The land is hot, arid, and sandy. It has some grassy vegetation, and I am open to having it be volcanic. The actual land itself is reminiscent of the Sonoran or Tanami Desert, or perhaps even the Atacama Desert, but with darker sand and a great amount of smoke covering the surface. What might be a reasonable explanation for this phenomenon? So, to summarize, I would like for the phenomena not interfere with:
-the dark, blackened coloration of the sand
-the grassy areas scattered around the desert
-the somewhat flat, rocky terrain.