I'd say that it links to culture. While ethnicity and culture are not synonymous, there's enough commonality to pose it as at least a contributing factor.
The other link is geography. Again, it's not a one-to-one but there's enough of an overlap to pose it as a contributor.
From the culture link, you get cuisine. I would pose that your taste in smells is at least partially linked to the kinds of food you eat and in particular the taste and smell of it.
From geography you get the local flora and fauna. Basically what things smell like where you grow up are a contributing factor.
I certainly don't think this is all there is to it. Just two things that I think are pieces of it.