True HEPA Tabletop Air Purifier can help capture up to 99.97 percent of airborne allergens and particles such as dust, pollen, pet dander, mold spores, tobacco and cooking/fireplace smoke particles. It also helps reduce odors and VOCs. Compact size is perfect for small rooms in the home office or nursery. Mechanical filtration process allows the fan to pull particle-filled air into the unit and forces that air through the HEPA filter to clean and circulate up to 4.8 times an hour in a 90 square foot room. Pre-filter is the first level of filtration and helps capture large particles including dust, lint and pet fur. Filter check/reset light reminds you to change your pre-filter every three months. Air purifier works with Honeywell A and A Plus Pre-Filters. Certified Honeywell True HEPA G Replacement filter helps capture microscopic allergens that are 0.3 microns and larger from passing through the filter. Replace your HEPA filter every 12 months for optimal cleaning performance.