The Honeywell Premium Air Purifier with True HEPA filter captures up to 99.97% of common household particles as small as 0.3 microns from the air passing through it, such as dust, pollen, tobacco smoke, and pet dander. It even helps capture airborne viruses and bacteria. The carbon pre-filter captures larger airborne particles and helps remove common household odours. The Intelli-Check Electronic Filter Indicator reminds you when to check the HEPA filter and when to replace the carbon pre-filter. The air purifier with three settings low, medium and high is suitable for people, who suffer from allergies or asthma.