The phenomenon that describes the fact the Daniel stopped noticing the scent was the concept of Adaption.
This is a phenomenon that describes the tendency of the brain to get used to certain things after being exposed to it for a long time.
The events the brain has gotten used to are still occurring, but the brain pays them less attention. This is what happened to Daniel with the smell - the brain started paying less attention to it.
Find out more on adaption at https://brainly.com/question/29594.