Why does fall, smell like fall?

Here's a topic for your next cocktail party:

Rachel Herz, neuroscientist to Radiolab says that essentially, what we perceive when we smell fall are the scent molecules coming from objects and organisms around us, but also the context we smell them in.

Temperature plays a big role in our sense of smell. 

When it gets cooler and drier outside, specific scents tend to stand out more — we’re able to kind of pull out the scent of leaves, the scent of bark, the scent of grass in more distinct ways.” 

Most of those smells are coming from the decomposition of leaves and in the fall it tends to rain more so the bark from the trees also gets wet.

Let us know what some of your favorite fall smells are.