Ionizing Air Cleaners: Where Negative is Positive
If you're considering an ionizing air purifier for your home, the safest bet may be to use a model that produces negative ions, not the more common positive ion generators.
Ionizing air cleaners or air purifiers claim to release ions that electrify and attract particles in the air - thus cleaning the air in your home. They run the gamut of price from low (you can get one from Bell + Howell for $32 after shipping and handling online) to exorbitant (the Airpura P600 retails at $1,200).
According to the Pima County Department of Environmental Quality in Arizona, air particles lead to asthma, lung damage, respiratory diseases, coughing, emphysema and even lung cancer. With so many negative risks, removing particles from home air is important - no doubt making ionizing air cleaners appear even more appealing on the surface.
What We Know
Several studies have found the ionizing process generates ozone. These studies have found that ionizing air cleaners typically emit between .5 and 4 mg of ozone per hour. The FDA ozone emission limit is 50ppb, and most air cleaners average an emission rate between 20 and 30 ppb, so they're within the safe level as defined by the FDA.
There is a caveat, however. Ozone interacts with many products found in home construction, thus leading to higher ozone levels. And high levels ozone can cause problems, including, lung damage, coughing, chest pain and can worsen respiratory diseases - essentially leading to the same issues the air purifier was purchased to rectify.
For instance, one study found that if the air cleaner is used as recommended (24/7/365), amounts of ozone in the areas around the air cleaner increase substantially—to output 5 times as much ozone after a week of operation. And maintenance matters. Regular bi-weekly cleaning of an ionizing cleaner can reduce ozone creation, but never fully eliminates it. Additionally, another study found that only 20% of users clean their air purifier as often as recommended—and discovered that failure to do so leads to a build up of ozone emission in the home.
What should you choose instead?
Air purification is necessary in your home to remove allergens or particulates and reduce respiratory problems. Fortunately, there are other options besides ozone-producing ion filters. Perhaps the best option to remove particles from the air is a high-efficiency particulate air (HEPA) filter. These filters are tested and proved - the American Lung Association recommends them as the most efficient mechanical filter to remove particles from the air.
HEPA filters remove 99.99% of particles .3 microns or larger, and removes 99.997% of particles .1 microns or larger. As a comparison of size, the finest human hair is 100 times the size of the dust, bacteria, smoke and pollen removed by a HEPA filter. Three top rated HEPA filters are the Whirlpool Whispure AP51030K , the Honeywell HPA 300, and the Winix PlasmaWave 5300 .
Another option is a non-ozone producing negative ion air purifier. These air purifiers not only clear particles from the air but may also help treat Seasonal Affective Disorder and depression. Be sure to choose a product that clearly states wif and how much ozone it emits. One such air purifier is the Wein VI-2500 High-Density Ionic Air Purifier .