A: 

Vog is volcanic smog. It contains sulfur dioxide which is the same gas that is released by burning coal and oil.  When sulfur dioxide mixes with dust and sunlight, it makes vog.
The big island of Hawaii has a lot of vog right now because Kilauea volcano formed a new vent which is pouring out sulfur dioxide.

Submitted by Maureen Delovio, Reference Department

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