8. Asphyxia is generally limited to enclosed spaces, and the deficiency of breathable air in an enclosed space can occur with any of the following conditions. Indicate the condition that will NOT cause asphyxia.

Normal atmospheric air contains 21% oxygen, which supports life and does not cause asphyxia; asphyxia results from oxygen depletion or displacement by other gases, such as those from rusting, inert gas, or cargo vapor.