DESC: Ninety-nine percent of particles in the air are invisible to the naked eye. Standard one-inch air filters trap less than 1% of those invisible particles, allowing them to re-circulate in your home. For the ultimate in clean air, count on the Honeywell Whole-House HEPA Air Cleaner. It captures 99.97% of pollutants from the air that passes through it, including cat dander, certain bacteria, pollens and more.