The Advanced Pure Air Newport 7500 Air Purifier features a powerful six-stage purification system. The air quality sensors monitor the pollution levels in your room and automatically adjust for maximum effectiveness and energy conservation. With unique Color-Ring Technology, you will easily be able to see the quality of the air in your room. The air goes through a series of filters, starting with a washable pre-filter to capture larger particles such as pet hair and pollen before they reach the HEPA or other filters. After the pre-filter, the air travels through a True HEPA filter with 'HEPA-Guard' proven 99.9% effective at capturing even smaller micron items like dust, pollen, pet dander, and more. The air then moves through an activated charcoal filter that absorbs toxic gases, chemical fumes, and odors. Lastly, the air gets filtered through a unique cold catalyst filter, which eliminates formaldehyde and other volatile organic compounds (VOCs).