An ionizer is an air purifier that imparts an electrical charge to particles that pass through it, causing them to clump together and settle out of the air, or stick to objects such as curtains or furniture in a room. Ionizers operate on the same principle as electrostatic precipitators, which also impart a charge to particles, but the latter uses charged plates to collect them.
If the indoor air quality problem you are most concerned about is odor, you might be wondering if an ionizer is good for odor removal. We will look at how ionizing air purifiers interact with pollutants that cause odors, including pet odors and cigarette odors, and determine if an ionizer is a safe and effective way to control odor in your home or car.
How do ionizers work on odors?
This is a slightly complicated question that requires a closer look at how ionizer technology works. Putting it succinctly: ionizers do not directly control odors; however, one possible side effect of producing ions is the control of some odors, but possibly in away that is harmful to your health.
Ionizers cause particulate pollutants to clump together because of the electrical charges the purifier gives them. These larger, heavier particles precipitate out of the air more quickly than they otherwise would—this removes them from the air, but causes a mess in the room because they can easily be kicked up again. Moreover, odors are caused by molecules of gaseous pollutants in the air, including volatile organic compounds (VOCs). But ionizers do not directly address gaseous pollutants at all, only particulate pollutants, so they do not directly remove odors from the air.
The high voltage charge that creates the ions also creates ozone gas. Ozone is a highly reactive gas that combines with other chemicals in the air, thus eliminating the original gaseous pollutant by converting it into something else. Therefore, the ozone that ionizers produce might remove odors by either masking them with the smell of ozone or by chemically altering the VOCs through the ozone reaction.
There are problems with using this approach to get rid of odors, however. For one thing, ozone itself is a toxin and a respiratory irritant, which is why the EPA does not recommend using air purifiers that create ozone. In an enclosed space, particularly in a car or a small room, ozone levels created by ionizers can exceed recommended levels.
Ozone itself has an odor that might be preferable to whatever unpleasant odor you are trying to remove. Some air purifiers even market this aspect, suggesting the purifier produces “clean air” or “pure air.” But the ozone smell is just replacing the original smell, not purifying the air at all (in addition to the potential harmfulness of the ozone itself).
In cases where the ozone reacts with VOCs and removes them, the reaction creates new chemical compounds in the air. Because ozone is so reactive, and because it is difficult to determine exactly what VOCs are in the air in your home, it is likewise impossible to predict exactly what chemicals will result when ozone reacts with something. Many of the products of ozone reactions are themselves toxic, including formaldehyde, acrolein, hydroperoxides and others [Weschler, 2006]. Ozone can even react with the oils in your skin to product potentially harmful compounds [Wisthaler & Weschler, 2010].
Problem odor sources and ionizers
Pet odor – Pet odors can come from accidents in the house or from natural skin oils that are present in your pet’s fur as your pet sheds, and this fur can become a source of odor in your house. Pet dander (tiny flakes of skin and fur) can also be an odor source. An ionizer could help with pet odors by removing some of these particles from the air. However, they will not be as effective for indoor accident smells, other than possibly masking the odor with the smell of ozone.
Mold and mildew – Mildew is a form of mold, which is a fungus that releases spores into the air. An ionizer would remove spores from the air, however the spores are not usually the source of the mildew smell. According to the EPA, “Some compounds produced by molds have strong smells and are volatile and quickly released into the air. These compounds are known as microbial volatile organic compounds (mVOCs). Because mVOCs often have strong or unpleasant odors, they can be the source of the ‘moldy odor’ or musty smell frequently associated with mold growth.” An ionizer would not be able to remove these VOCs from the air.
Smoke – Tobacco smoke, marijuana smoke and wood smoke are all cocktails of numerous toxic gaseous pollutants, along with particles of ash. Ionizers will help remove the particles form the air, but this will not address the VOCs that primarily cause the smell from smoke. These VOCs can include benzene, cadmium, vinyl chloride, ethylene oxide and arsenic. In addition, ozone can react with any of the chemicals in unpredictable ways, creating still more potentially problematic compounds in the air.
Car interiors – Most smells in your car are caused by VOCs, whether it is from outgassing upholstery, tobacco smoke or mildew. Ionizers will not remove these odors, although the ozone smell might mask them. However, in the small enclosed space of a car, ozone build-up would be a significant problem. Because plug-in ionizers are the most common air purifiers for cars, this may seem like your only option. If you must use an ionizer in your car, keep the windows at least partly down to release any built up ozone.
Cooking smells – Much like smoke, cooking smells are made up mostly from VOCs released by the food when it is heated, along with some particles. An ionizer will remove the particles, but will mostly not affect the odor. The ozone by-product of an ionizer may remove some VOCs from cooking and reduce the smell, but as previously discussed, this is not an ideal solution.
Other ways to get rid of odors
The best way to deal with unpleasant odors is to get rid of the source of the odor. Dealing with mold, cutting down on smoking or moving it outdoors, bathing a smelly pet or using a kitchen fan while cooking will prevent many odor problems.
If there is no other way to address a persistent odor, an option that is often used is a carbon filter. Carbon filters are designed to remove VOCs from the air. They will not remove particles, so they may need to be combined with another air purification technology. In fact, you may find ionizers that are combined with a carbon filter to remove odors. In this case, the carbon is probably doing most of the work removing odors, so you can skip the ionizer and just get a carbon filter.
Whereas carbon filters merely trap VOCs temporarily, Molekule’s PECO (Photo Electrochemical Oxidation) technology uses a photocatalytic process to destroy both allergens and odor-causing VOC molecules. This means a PECO air purifier would remove the toxic chemicals in tobacco smoke from the air by breaking it down into harmless components of water vapor and carbon dioxide, removing the smell without producing any ozone. PECO technology also destroys allergens such as pet dander and mold in the air, which can cause odors as well. This could be a great option for rooms with multiple types of indoor air pollutants and persistent or recurring odor problems.
Although ionizers may indirectly mask or chemically alter odors because of the ozone, the ozone they produce as a byproduct makes them a less-than-ideal choice for sensitive groups. Ultimately, these devices were not designed to handle odors, and if you’d like to get rid of unwanted odors in your home without placing you and your loved ones at risk, consider these other more effective, and less hazardous technologies instead.