Farms in the Sky?

There is an interesting twist to buying local produce. A NY Times article outlines farm buildings in metro areas:

What if “eating local” in Shanghai or New York meant getting your fresh produce from five blocks away? And what if skyscrapers grew off the grid, as verdant, self-sustaining towers where city slickers cultivated their own food?

I think there might be a couple of olfactory issues that need to be worked out, however an interesting concept wouldn’t you say?