User blog comment:Evans0305/Game Theory: BioShock/@comment-3567720-20110820172550/@comment-1401334-20110821034557

I might be remembering wrong, but I think at one point in the novel, BioShock: Rapture, the author mentions that the Lighthouse was used to take air from the surface and pump it down through tubes to the city. Of course, the book may not be canon, but it is a possibility.