Air filters for home use can be divided into those that filter the air, called HEPA filters, and electrostatic air filters.
HEPA filters consist of a filter and carbon prefilter, which together are capable of filtering particles as small as 0.2 micrometers from room air. HEPA filters will effectively remove both airborne allergens, including molds, animal danders, and pollens, as well as other particles, such as volatile organic compounds and smoke.House dust mite allergens do not remain airborne for more than a few minutes after being disturbed and are therefore not accessible to air filters.
Electrostatic filters are designed to place a negative ionic charge upon airborne particles, which then aggregate onto a metal plate in the filter. This technology has proven appealing because these filtration devices are small and noiseless. However, they have not proven effective in removing allergens or other particles. In addition, the ozone generated by these machines has proven to be irritating to the respiratory tracts of patients with asthma.
Electrostatic air filter
A filter that places a negative ionic charge upon airborne particles, which then aggregate onto a metal plate in the filter.