why are the smoky mountains smoky

The Smoky Mountains are "smoky" because of the natural fog created by volatile organic compounds (VOCs) released from the abundant vegetation in the area. These VOCs evaporate and combine to form a vapor or fog that blankets the mountains, giving them their characteristic smoky appearance. Additionally, the fog has a blue tint because the vapor molecules scatter blue light from the sky. The conditions in the Smoky Mountains—high rainfall, humidity, sunlight, and stagnant air—make this blue smoky fog particularly visible and prominent. Although air pollution contributes somewhat to the haze, about 80% of the "smoke" is from natural sources like VOCs from plants.