The Blueair 270E is AHAM certified for rooms up to 240 square feet. A perfect bedroom companion, the Blueair 270E packs a complete, high-performande air purifier into a beautifully compact design that's incredibly quiet. This unit doesn't have to be restricted to just the bedroom. It's also great in small areas and workspaces to get rid of pesky airborne allergens including, but not limited to, pollen, dust, smoke, pet danger, bacteria and mold spores. ALL that remains is impeccably clean air. Near silent operation In direct comparative. noise testing of our unit and other mechanical air cleaners, the Blueair units were found to be the quietest. Particle and gas sensors The electronic particle sensor determines whether the amount of airborne particles is above or below the acceptable limit. Progressive filer structure