The very name "air purifier" means that such a device serves to purify the air, from the most visible large components (fluff, dust) to microscopic particles invisible to the eye.
The purpose of modern air purifiers is to rid the air of such impurities.
A set of filters allows you to purify the air, from the coarsest dust to the finest one - 0.3 microns, as well as remove extraneous odors from the air and additionally enrich the air with anions that increase the general tone of the human body using an ionizer.