The forms of things unknown, the poet's pen
Turns them to shapes and gives to airy nothing
A local habitation and a name.
.................Midsummer Night's Dream, Act V, Scene 1
Watching dust, dirt, leaves and tumbleweeds roll past the other evening, I recalled that our local winds blow rather consistently from the Southwest. The average wind over the country is from the West. How long, I wondered, will it take for the whole West Coast to blow all the way to the East Coast?
Quite a while, I guess. It's dry here, so dust and sand blow a lot. A whole big field of gypsum dunes (White Sands National Monument) covers many squares miles of Otero County, all evaporites blown off a tiny lake. Much of the country isn't much like that. Even here most of the blown matter is biological: leaves, pollen, tumbleweeds, and bugs.
That biological matter is indeed a sort of "airy nothing," composed almost entirely of elements from the air: carbon, oxygen, nitrogen, and water. The winds that carry our sand east will carry the organic matter just far enough to dissolve back into the air that blows it around the world and back to the West Coast.