Combustion Air

Inspected a mobile home that has a Miller oil fired furnace manufactured 2004. A hose is attached to the burner for combustion air intake, that terminates in the enclosed crawl space (typical skirting around the mobile). Is it acceptable to draw air from a damp crawlspace, or should it terminate at the exterior?

John in my area C air is allowed to be taken from a crawl space or the attic with the assumption that the space is not perfectly sealed.

Same here.