The Blue Haze of the Great Smoky Mountains

Traveling in North Carolina and Tennessee recently, I had the opportunity to visit Great Smoky Mountains National Park. While renowned for its “wondrous biodiversity”, the park’s name is derived from a localized atmospheric phenomenon.

The Cherokee, who originally inhabited the area, called the mountains, “Shaconage”, meaning “place of the blue smoke”. It refers to the smoke-like bluish haze that hovers over the park’s rugged peaks and valleys, especially after a rainstorm. According to the NPS, it is a natural by-product of plant transpiration.

While all trees and plants exhale water vapor, the conifer trees in the park also emit terpenes – a naturally occurring organic compound. Released in large quantities, the mix of terpenes and moisture react with natural low level ozone molecules to form tiny particles that scatter blue light. As a result, the mountains appear to be bathed in a gauzy blue mist.

In recent years, according to the NPS, human-made air pollution has been obscuring the Smokies’ signature blue haze.

View of blue haze in Great Smoky Mountains National Park.  Image Credit: NPS

View of the bluish- haze in Great Smoky Mountains National Park. Image Credit: NPS

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About Melissa Fleming

Melissa Fleming is an environmental communicator and visual artist working at the intersection of art and science. She is passionate about exploring, learning, and sharing information about the natural world. She has presented her interdisciplinary work in a variety of mediums at venues and conferences around the world.