Top comes out on the roof:
Not sure what happens below. Haven't gone under the house to inspect. Seems like a vent that travels through the wall space, but unclear why it would do that.
Any ideas what its purpose is?
Furnace exhaust would be ideal, because I don't have a furnace anymore and I do need a vent. I guess it depends if its safe to remove, I am a bit concerned it may be asbestos?