The “smoke” from the Smoky Mountains is actually fog that comes from the area’s vegetation. Plants take in carbon dioxide and give off oxygen. Plants also exhale something called “volatile organic compounds”, or VOCs.
VOCs may sound scary, but when they are released from plants, they are completely natural.
In addition to causing various scents and odors, a high concentration of VOCs can also cause fog. VOCs are chemicals that have a high vapor pressure, which means that they can easily form vapors at room temperature. The millions of trees, bushes, and other plants in the Great Smoky Mountains all give off vapor, which comes together to create the fog that gives the mountains their signature smoky look.
The colors of Fall contrast nicely against the “smoke.”