The Chemistry of Air Purification

It's amazing to think that we've gone from having no idea what air is, to knowing its composition intimately, and even having the ability to filter what's in it. We have produced machines that can remove both pathogens as well as harmful small molecules from the air, and we have innovated those machines to the point where they are affordable enough for home use. How do these machines work? What do they do and do they do it? Let's break it down!