Hi Yanky,
I don't know if there is a clear-cut answer to your question. I lost almost all of my sense of smell with my TBI. I can still smell a few things. Bleach, nitric gas, mowed lawns, and patchouli. Yuck

At least the severity of the scents has weakened a lot! That's the only good part of it in my opinion.
Best wishes to you ~ and welcome to Neuro Talk!
Shez