Ah propinquity, a word meaning "proximity or physical closeness." Your propinquity to someone in a conversation will affect whether you can smell his breath or not.
Propinquity had a brief moment in the sun on a television show in the 1950s called Dobie Gillis. There was an episode in which the nerdy girl, who was in love with Dobie Gillis, decided to get him to love her back. How? Propinquity! And so she explained it to him, over and over and over, theorizing that just being near someone long enough would tip them over the edge into love. Sadly for her, it didn’t work, but everyone who has ever seen or heard of the episode has the meaning of propinquity burned into their brain.