A perfect bedroom companion, the Blueair 203 packs a complete, high-performance air purifier into a beautifully compact design that incredibly quiet. The Blueair 203 doesn't have to be restricted to just the bedroom. Its also great in small areas and workspaces to get rid of pesky airborne allergens, such as pollen, dust, smoke, and mold spores. All that remains is impeccably clean air. The 203 Air Purifiers intake air through the back of the unit. The air is passed through the electrostatic HEPA-type filter where the small particles are trapped, and then through the ionization chamber where the air mixes with negative ions. Negative ions are then released with the clean air through the top of the unit. The ions collide with the particles in the room air and the particles become charged. When the air cycles back through the unit, the charged particles cling to the electrostatic filter media. The combined filtration technologies allow the Blueair Air Purifiers to achieve 99.97% filtration efficiency.