ok so I stumbled cross this becuse in n episode of ST:TNG (S3E01 "Evolution") there is mlfunction tht releses "nitrogen oxide" on the bridge nd everyone is coughing.

so I looked up different gses tht hve N nd O, none hve tht exct nme. noticed tht nitric oxide is pprently only produced when you brethe in through your nose:

Nasal breathing produces nitric oxide within the body, while oral breathing does not.

nywy the reference led to this rticle