I've had occasion to get up in the attic of my (new, to me) house recently. There is what appears to be dirt all over everything up there, with actual accumulation in places.
This is a 2-story 1964 stick built stucco exterior home built over a dirt crawl space. There is no plastic or anything over top of the dirt. The walls are completely uninsulated.
The only possible way I can conceive of dirt getting into the attic is stack effect sucking dirt out of the crawlspace and up the inside of the walls where it then settles out in the attic.
Anybody ever heard of something like this or can identify another possible source for dirt in an attic?