Air purifiers come in many different types. Some models clean the air by forcing it through a physical filter, capturing particles and removing them from suspension. Another type of air purifier is an ionizer, which uses an electrical field to remove airborne contaminants. Ionizers offer advantages and disadvantages compared to other types of purifiers.
Electrical Attraction
One of the basic laws of physics is that particles bearing opposing charges will attract one another, while particles with like charges will repel. Under most circumstances, airborne contaminants bear a positive charge, as do walls, floors and other surfaces within a room. These like charges keep the particles from settling out of the air, keeping them circulating where they can cause allergic reactions.
Ionization
An air ionizer produces negatively charged ions, which attach themselves to nearby positively charged particles. If enough ions attach themselves to a single particle, they can actually change its polarity, making it negatively charged as well. This newly negative particle will then adhere to any positively charged surface in the room. These particles can also stick to other positively charged particles, forming large clumps that are more likely to fall to the ground.
Benefits
Air ionizers work quickly, spreading a negative electric charge through the air in a room and affecting all types of airborne contaminants. These units are quieter than filter-based air purifiers, as they don't require a constant high rate of airflow to clean the air. Ionizers also require less maintenance than other types of units, which require regular replacement of filters or regular cleaning of electrostatic collection plates to keep the purifiers operating at full capacity.
Drawbacks
One problem with an air ionizer and purifier is that it does not actually remove contaminants from the environment. Although an ionizer can quickly settle the airborne particles in a room, eventually the charge will fade, and the particles will float through the air again. An ionized room requires regular cleaning, such as dusting, mopping or vacuuming; otherwise, any activity will simply stir up the allergens once more. Another drawback is that negatively charged particles can stick to mucous membranes in the body, increasing the chances of triggering an allergic reaction.
Dangers
One side effect of the air ionization process is the creation of ozone, according to the Environmental Protection Agency. Ozone is an unstable oxygen molecule that can oxidize anything organic it touches, and is hazardous in large concentrations. Although most ionizers create only trace amounts of ozone, they can still be dangerous to small animals and anyone with a respiratory condition.
References
- Air Purifiers: Negative Ion Air Purifiers
- Indoor Purifiers: How Negative Ions and Ozone Clean the Air
- Allergy Consumer Review: Everything You Need To Know But Were Afraid To Ask
- Asthma and Allergy Foundation of America: Air Filters
- U.S. Environmental Protection Agency: Ozone Generators That Are Sold As Air Cleaners
