The Holmes aer1 Desktop Air Purifier with HEPA-Type Filter captures particles as small as 2 microns from air passing through the filter, and operates quietly to remove up to 99% of airborne particles such as pollen, dust, mold, pet dander, and smoke, providing relief from odor and irritants in the air so you can breathe comfortably. The air filter also offers 30% better dust elimination than traditional Type A HAPF30 filters at clean air delivery rate passing through the filter. You can see the particles being accumulated through the Visipure Air Filter Window, and this Holmes air purifier has a filter reminder, so you know when it's time to change the filter. The space-saving design easily fits in any corner of the room, leaving clean and crisp air all around your home. The optional ionizer also helps to ensures smaller particles are more easily captured, and helps tackle odors.