I'm a bit late into the ozone discussion, but you're going to get my dimes worth anyway.
St. Elmo's fire and Ozone smell can be found from sea level and upwards when the conditions are right. On ships passing through tropical zones, St. Elmo's fire is often seen attaching itself to a yardarm of a mast, or even the outer corner of a bridge wing. The Ozone smell comes with the event.
Having had a lot to do with Ozone generators in a former life, I do know the smell of Ozone, and the linkage of St. Elmo's fire to that of the Ozone smell is also one I know well.
The PNF had crossed the ITCZ many times and was well aware of what he saw and smelled, and any conjecture that the smell was of electrical origin is just that - conjecture.