Ah ok. Well the fact remains you have an exhaust with elevated nox. So the 3 options are to stop the nox being created to start with (no nitrogen), convert th

Ah ok. Well the fact remains you have an exhaust with elevated nox. So the 3 options are to stop the nox being created to start with (no nitrogen), convert the nox into something else (nitrous oxide?) or release/store/use the nox for something. I'm not a chemist so I don't know what's possible / economic, thus the question.