Question

Why can we not use the Nitrogen that we breath in

Answer 1

because it is an insert gas and it is very dangerous for ear and our nose

Answer 2

Nitrogen is an inert gas — meaning it doesn't chemically react with other gases — and it isn't toxic. But breathing pure nitrogen is deadly. That's because the gas displaces oxygen in the lungs. Unconsciousness can occur within one or two breaths, according to the U.S. Chemical Safety and Hazard Investigation Board.