 | Free Ground Shipping (In-Stock) The Surround Air S4000 Air Purifier utilizes six filtration technologies including a TiO2 coated Photocatalytic Oxidation and Activated Carbon filter, to remove 99.97% of particulates from the air.The Surround Air S4000-TIO2 replacement filter helps destroy chemical molecules, bacteria, and odors, and is compatible with the S4000 Air Purifier. Regularly replace the filter every 12 months to ensure proper particle abatement. | | SEE IT |