Why is "air" needed here? It seems like "Tha Seumas bhioran" would be James is excited, but "air" is in there.
Because it's an idiom. Bioran is a pointy stick. So the phrase translates to "James is on a pointy stick" or "a pointy edge". Along that lines.
And if the air were not there then it would be bioran as the bh is caused by the preceding air.
I love this idiom hahahaha