Ionic air cleaners induce an electrostatic charge on dust particles passing through them. The enlarged particles deposit on room surfaces or are collected on metal plates that need to be cleaned on a weekly basis. Many popular models are not recommended by consumers' groups for failing to clean the air and releasing potentially unhealthy levels of ozone.

Indoor ozone is a lung irritant that can worsen asthma, deaden sense of smell, raise sensitivity to pollen and mold, and may even cause permanent lung damage. The United States Environmental Protection Agency does not recommend using ozone generators as indoor air cleaners.

Filter-based air purifiers capture particles rather than oxidize airborne contaminants. The filters need to be replaced when dirty, which imposes a high cost of ownership. Some units can produce annoying noise levels. Carbon filters, when included, adsorb odors and gases, but they can also reemit pollutants.

Ultraviolet or UV air purifiers use Germicidal type UVC radiation to kill germs by destroying their DNA. UVC radiation is hazardous to all living things. Germicidal UV air purifiers do not remove gases and can produce ozone.