Why are the Blue Ridge Mountains blue?

Because of the hydrocarbon released in the air by the trees. But I think it can be seen only from distance...Why are the Blue Ridge Mountains blue?
He's right. It can only be seen from a distance. I have the luxurt of living in NC and we get to drive by them often and they are always in a haze of purple and blue when you see them. But they are like any othe rmountain up close.Why are the Blue Ridge Mountains blue?
The National Parks Service uses Vietnam era C-130s that were used for spraying Agent Orange to lay down a mist of blue dye. Depending on the rain fall for the year depends on how often they have to do it. Any where from 2-4 times per. They don't spray they entire mountain range, just along the roads.