Three plain air purifier shapes on a pale floor

Types of air purifiers

Filters, electronic air cleaners, UV, and ozone generators.

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Mechanical filters

A mechanical filter catches particles as air passes through it. EPA calls HEPA a type of pleated mechanical air filter.

Gas filters

EPA says that to filter gases, you should choose a portable air cleaner with an activated carbon filter or other filter designed to remove gases.

Electrostatic precipitators and ionizers

The California Air Resources Board (CARB) says air cleaners that use ionizers and electrostatic precipitators are designed to electrically charge particles in the air and cause them to attach to surfaces in the room. It says ozone is released through the charging process, although these devices typically emit much less ozone than ozone generators.

UV, PCO, and plasma

EPA says research has not yet shown that plasma, photocatalytic oxidation (PCO), or ultraviolet (UV) light can remove gases effectively in portable residential air cleaners. It also says UV lights without adequate lamp coatings and plasma air cleaners may have the potential to emit ozone.

Ozone generators

EPA says ozone generators that are sold as air cleaners intentionally produce the gas ozone, and that no federal government agency has approved these devices for use in occupied spaces. Our ozone guide covers this in full.

Which type fits a home?

We do not pick a type or a model. EPA says to avoid portable air cleaners and furnace or HVAC filters that intentionally produce ozone.

Types of air cleaners. Per EPA and CARB.

Sources: EPA, Guide to Air Cleaners in the Home; EPA, What is a HEPA filter?; California Air Resources Board, Hazardous Ozone-Generating Air Purifiers; EPA, Ozone Generators that are Sold as Air Cleaners; EPA, What are ionizers and other ozone generating air cleaners?.

FAQ

Do UV air purifiers remove odors?

EPA groups odors with gases, and says research has not yet shown that UV light can remove gases effectively in portable residential air cleaners.

Is an electrostatic precipitator an ozone generator?

CARB says ionizers and electrostatic precipitators emit ozone as a by-product of their design and function, although they typically emit much less ozone than ozone generators, which emit ozone on purpose. EPA says ozone is produced indirectly by ion generators and some other electronic air cleaners and directly by ozone generators.

General information only. An air purifier is not a substitute for ventilation, for removing the source of a pollutant, or for medical care. Read and follow the maker's manual. The California Air Resources Board strongly advises against the use of ozone generators in spaces occupied by people or animals. If you have asthma, allergies, or heart or lung disease, talk to your doctor. During wildfire smoke, follow local officials and be ready to evacuate. In an emergency, call 911.

An open window letting fresh air into a calm room

Ozone generators and ionizers

Why ozone is a health risk.

HEPA filters, explained

What the 99.97% means.

A dark filter block leaning against a shallow stone dish of black granules on grey linen

Activated carbon filters, explained

Gases, odors, and VOCs.

Next: ozone and ionizers