How the Blue Ridge Mountains (Almost) Lost Their Blue

The Blue Ridge Mountains are known for their blue haze, caused by VOCs emitted by trees. These VOCs, while contributing to the beauty of the mountains, also play a role in forming ground-level ozone, a harmful pollutant. The region's biodiversity is due to its history as a refuge during ice ages. Pollution from coal and vehicles has historically affected air quality and visibility, but regulations like the Clean Air Act have improved conditions. The shift from coal to cleaner energy sources has further enhanced air quality, restoring the mountains' iconic blue appearance.

What is the primary reason for the Blue Ridge Mountains' biodiversity?

• Refuge during ice ages

• Rich soil composition

• High altitude

• Proximity to the equator

How do VOCs affect the appearance of the Blue Ridge Mountains?

• They block sunlight completely

• They reflect green light

• They scatter blue and violet light

• They absorb all light wavelengths

What environmental paradox is associated with VOCs?

• They only benefit plant growth

• They reduce air pollution

• They contribute to ozone formation

• They are harmless to humans

What was a major cause of high ozone levels in the Blue Ridge Mountains during the 1990s?

• Increased tourism

• Natural VOC emissions

• Pollution from coal production

• Deforestation

What was the impact of the Clean Air Act on the Blue Ridge Mountains?

• Decreased biodiversity

• Increased coal production

• Higher ozone levels

• Improved air quality and visibility

How has the energy landscape changed in the US since 2015?

• Increased reliance on coal

• More coal plants being built

• No change in energy sources

• Shift towards natural gas and renewables

What is the current percentage of electricity in the US that comes from coal?

• 30%

• 10%

• 50%

• 20%