Phenomena

Cleaning the Skies

Featured Video Play Icon

Those of us who live in urban environments have experienced the clear, pollution-free air that comes after a rainstorm. But how exactly does rain clean the air? Air pollution typically has both gaseous and particulate components to it. As a raindrop falls, it experiences collision after collision with those particles. Depending on the particle’s surface characteristics — is it hydrophilic or hydrophobic? — and its momentum during impact, it can get trapped in the raindrop, skip off, or even pass through entirely. The physics, it turns out, are identical to those of a rock falling into or skipping off a lake — even though the raindrop and particle might be 1000 times smaller! (Image and video credit: N. Speirs et al.)

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: