4 Filtration levels - Pre-filter Activated carbon filter Allergy+ Nanocaptur+. Pre-filter captures hair and dust. Active Carbon filter removes smoke odors and VOCs. Allergy+ filter for fine particles pollen allergens bacteria viruses and more. NanoCaptur+ filter permanently destroys formaldehyde. Intelligent filtration system detects room's pollution level. Automatic speed change from levels 1 to 5 on day mode and 1 to 2 on night mode. Timer up to 8 hours with auto shutoff. For rooms up to 243 square feet. CADR rating (smoke): 157.