Something olfactory has to do with the sense of smell. The odor from that factory is a symphony of olfactory delights. Not.
Though we typically think of dogs as the olfactory champions of the world, what with their remarkable ability to sniff out practically anything, the true title belongs to the polar bear. Healthy, adult polar bears possess olfactory gifts that boggle the mind: they can smell a seal under the ice from over a kilometer away. One way to try to remember the meaning of the word olfactory is to think of factory. Your nose is the "factory" where odors are processed. What visual is to the eyes, olfactory is to the nose.