odorant vs olfactory

odorant

adj
  • Having an odour/odor. 

noun
  • Any substance that has a distinctive smell, especially one added to something (such as household gas) for safety purposes 

olfactory

adj
  • Concerning the sense of smell. 

noun
  • The sense of smell. 

How often have the words odorant and olfactory occurred in a corpus of books? (source: Google Ngram Viewer )