The Honeywell Fresher Air Tabletop Air Purifier utilizes a collection of intuitive features to help capture up to 99% of fine particles such as dust, pollen, smoke and pet dander. This makes it an excellent choice as an air purifier for allergies or as a pet air purifier. The personal air purifier uses a Honeywell Dual Action HEPA Type Filter that's suitable for small rooms (4.8 x air changes per hour in a 100 sq. ft.). Dual Action HEPA-Type Filters include an activated carbon pre-filter layer that can assist in the general reduction of odors. It is generally recommended that the HEPA-Type filter of this portable air purifier be replaced every four months. This tabletop air purifier includes a 3 year warranty.