This is the only air purifier that combines the top six technologies into one unit: true HEPA filter for dust and allergens, germicidal UV Lamp to destroy micro-organisms, activated carbon filter for chemicals, smoke, odors, ionizer for particles and bacteria, programmable sanitizer for odors, and anti-bacterial pre-filter for larger particles. Tests show that true HEPA filters (recommended by the Dept. of Homeland Security) are more effective than any other type of air filter