Choosing an Ionic Air Purifier

Miriam Stevens, Clean Air Advice
July 2006

Ionic air purifiers are known by many names: electronic air cleaner, electrostatic air cleaner, electronic precipitator, ionic air cleaner—among others. Despite the range of terms used to describe these products, they basically work in one of two ways: Ion Generators work by charging particles in the air, which are then attracted to each other, and to surfaces in the room, and then settle out of the air where they no longer pose a threat. Electrostatic Precipitators, on the other hand, not only charge the airborne particles, but also use oppositely-charged collection plates to trap the pollutant particles, offering a more convenient cleanup solution.

ADVANTAGES AND DISADVANTAGES

Like any high-tech solution, ionic air cleaners have their advantages and disadvantages. Among the major advantages of electronic air purifiers is their low energy consumption and quiet or nearly silent operation. Even these benefits, however, bring their own drawbacks: many "energy efficient" ionic air cleaners claim to save on energy costs by omitting the powerful fans used in competing technologies, such as HEPA Filter air cleaners. The problem with this approach is that in order to clean the air in a room, an air purifier must have a substantial air flow through the unit. Without the fan, many ionic air cleaners simply don't move enough air through the unit to do much good at all. At Clean Air Advice, we agree with testing organizations like Consumer Reports who have found many of these ionic air purifiers ineffective in home use. This includes many of the popular—or more to the point—well-marketed units like the Sharper Image Ionic Breeze and Oreck XL "air cleaners" which in reality do very little actual cleaning at all.

WHAT TO LOOK FOR

If you're still convinced that an ionic air purifier is the right choice for you, there are some things you should consider to make sure you're getting a quality product that does what it is intended to do: obviously, you want an air cleaner that actually cleans the air!

First of all, make sure the unit moves the air. Be highly suspicious of the claims of any ionizer or "ion generator" that claims to work without a fan. While the fanless ionic models show some effectiveness in small rooms, you can bet they do little good at all if there's not enough air circulation through the unit. Our tests have shown—and most other reviewers agree—that air cleaners with fans are the most effective option. If fan noise is a problem for you, look into buying a larger unit than you need, and running the fan on low speed while sleeping. Ionic air cleaners can remove particles from the air, but they must come into contact with the air before they can clean it.

Secondly, be aware that all ionic air cleaner devices produce some ozone; it's a natural by-product of the ionizing process. Some manufacturers actually claim this as a benefit, as ozone does in fact neutralize odors in the air, leaving a "fresh" smell. But while the effects of low-level ozone on otherwise healthy individuals is debatable, studies suggest that even low levels of ozone in the air you breathe can be dangerous for asthmatics and sufferers of other respiratory ailments. Some groups, such as the American Lung Association, recommend avoiding any amount of ozone. Some users have found little long-term health effects, but still complain about headaches and even dizziness brought on by the smell of ozone.

Should you wish to purchase an ionic air cleaner, we recommend carefully checking the ozone output before you buy. If the manufacturer does not give specifications for ozone output, ask. If you still can't find the answer, find another product.

A BETTER SOLUTION

Based on the evidence, it's hard to recommend any type of air purifier which uses ionic technology or electrostatic precipitation as its sole method cleaning the air, especially when compared against HEPA filter models which are proven to work better, and with only a small increase in energy consumption and overall cost of operation. But that's not to say that ionizing and electrostatic methods have no place in the market—far from it in fact. Some of the highest-rated and most effective air cleaners and air purifiers on the market actually employ ionic air cleaning in addition to other technologies. High-performance air purifiers from Friedrich, BlueAir, and IQAir, among others, combine highly-effective HEPA filtration with electrostatic charging of incoming air, increasing the effectiveness of the filter and the overall efficiency of the air cleaner.

Some of these so-called Hybrid Air Cleaners use an ionizer inside the unit to charge the particles in the incoming air, others apply an electrostatic charge to the filter itself; both methods result in increased effectiveness over either type of technology alone. Based on our reviews of air cleaners and air purifier products, Clean Air Advice has found these hybrid machines, sometimes called Electrostatic Filters, to be among the most effective, and often most efficient, air cleaners on the market today.

Furthermore, because the ionizer used in a hybrid air cleaner has less work to do, ozone output by these units is negligible, if any at all—unlike the "air ionizers" which produce large numbers of charged ions which are released into the air. If a health condition requires you to avoid any level of ozone whatsoever, you may want to consider a simple HEPA filter alone; otherwise, a hybrid air purifier with ionizing technology combined with an electrostatic filter and/or HEPA filter may be your best bet for clean and healthy air in your home or office.

Related Articles

• Air Purifier and Air Cleaner Technologies
• Choosing a HEPA Filter Air Cleaner
• Sharper Image Ionic Breeze and Oreck XL Air Purifier Tests Results
• What Are You Breathing?
• 12 Steps to Improve Indoor Air Quality