What is the difference between UV Air Purifiers and air filtration?

Harmful or poor indoor air quality is comprised of air pollutants like particulates, germs and gases. Air filtration can mainly deal with particulates in air by reducing particulate down to a specific size, like HEPA rated particulate arresters, or down to a percentage of a range of sizes as a MERV rated air cleaner does. On the other hand, air purifiers can mainly deal with air pollutants like germs and gases, that are too small for a HEPA or MERV rated air cleaners to trap. Germs passing by a UVC lamp will be reduced. Gases passing by a UVC lamp will be broken down through an oxidation process that occurs when the UVC lamp shines on the PCO module of the air purifier.