These filters capture 90% of large allergens like mould spores and pet dander from the air passing through the filter. They also attract microscopic allergens, including dust, smoke, smog, bacteria, and particles that can carry viruses. Each filter lasts 3 months. This model meets the American Lung Association Health House Indoor Air Quality Guidelines. No unnecessary antimicrobial chemicals were added. Plus, its filtering material inhibits the growth of fungi, mould, mildew, or bacteria in normal use.