Air purifiers are a great way to reduce the amount of hazardous pollutants in the air, allowing you to breathe better and reduce the spread of bacteria and virus particles. The Environmental Protection Agency (EPA) states that while air purifiers can reduce indoor air pollution, they cannot remove all particles from the air. UV air purifiers can convert oxygen and water molecules to ozone and hydroxyl, which can then react with contaminants and ultimately destroy them. However, ozone can be extremely harmful, so any good UV filter should minimize the amount of ozone in the air.
Bipolar ionization also works by surrounding air particles with positive and negative ions, destroying germs and pathogens, and helping air particles fall to the ground and enter the building's air filter. Portable air purifiers are particularly useful when additional ventilation with outdoor air is not possible without compromising indoor comfort (temperature or humidity) or when outdoor air pollution is high. Portable air filters and HVAC filters can reduce indoor air pollution; however, they cannot remove all pollutants from the air. Air purifiers capture a high percentage of airborne allergens and irritants that flow through filters.
The CADR for air purifiers is based on standards set by the Appliance Manufacturers Association (AHAM). Carbon filtration uses a highly porous form of carbon to trap chemicals and recycle fresh air back to the room. The higher the CADR number for each pollutant, the faster the unit filters the air for contaminants in a given size range. Ozone generating air purifiers create ozone to clean the air through chemical interactions that alter the compounds of pollutants, but this is also the mechanism by which ozone exerts harmful health effects.
Air purifiers often use a filter, electrostatic, or ultraviolet light emission technology to remove particles from the air. The Appliance Manufacturers Association (AHAM) recommends that the CADR of your air purifier be equal to at least two-thirds of the area of the room. Air purifiers usually consist of a filter, or several filters, and a fan that draws in and circulates the air. The EPA, ASHRAE and CDC recommend upgrading air filters to the highest possible efficiency that is compatible with the system and verifying filter fit to minimize filter bypass.