Air purifiers that effectively remove allergens from the air in your house can be an effective way to ease the symptoms of environmental allergies caused by pets and dust mites as well as seasonal allergies. Ionizers are air purifiers use an electric charge to remove particles from the air, but can they do so for allergens? More importantly, will they help with allergy symptoms? We will take a close look at how ionizers work and determine if they will help you and your family with allergy symptoms.
How do ionizers affect allergens?
Some allergens are small enough to be suspended in the air and can cause an allergic reaction if you inhale them. Typical environmental allergens include pet dander, dust mites (or more specifically, dust mite feces), mold spores and pollen.
A review of scientific research found that, “ionic electrostatic room air cleaners provide little or no benefit” when it comes to reducing allergy symptoms and controlling allergens in an indoor environment (Sublett,2011).
This ineffectiveness against allergens is due to how ionizers work. Because an ionizer causes particles to be suspended in the air to precipitate out of the air onto nearby surfaces, allergens, dust and other particles end up on the floor, in the carpet or even stuck to curtains and on furniture. The ionizer does not actually destroy allergens, and any air currents in the room, such as from the HVAC system or simply someone walking through, will kick the allergens back into the air again.
Why ionizers are not effective against allergens
Ionizers work by imparting an electrical charge to any particles that move through them. Most of them use a high-voltage wire to do this, usually giving a negative charge to the particles. Once the particles are charged, they are attracted to anything with the opposite charge. As they float through the air, they will encounter other particles, and opposite charged particles will stick together. The particles will gradually form larger clumps. Since these clumps are heavier, they precipitate out of the air and land on a nearby surface.
Alternately, the charged particles might be attracted to a surface with the opposite charge, which could be your TV screen or computer monitor, or it could be your furniture or curtains (if static electricity has given them a charge).
The ionizer does not collect or destroy the particles—they simply fall out of the air. This means the area “downstream” from the ionizer will get messy and require frequent cleanup. Moreover, the allergens are still present and will get kicked back into the air again when the furnace or air-conditioning turns on, or even by air currents caused by you or a pet walking by. At that point, you will be basically back where you started, and the ionizer will have done nothing to improve your indoor air quality. Any pet dander, pollen, dust mites or mold spores will still be present and floating in your house, waiting to be inhaled.
Pet dander can be especially problematic. These microscopic flakes of skin that have sloughed off of the pet float easily in the air, but their jagged shape makes them “sticky,” because they get hooked onto microscopic features in places like carpet fibers or furniture. Thus dander that has been precipitated out of the air by an ionizer is difficult to remove, even with vacuuming.
Ionizers also produce ozone as a side effect of the high-voltage charge used to create ions. Ozone is a respiratory irritant, and the EPA has found that some ionizers can create ozone concentrations that exceed health standards, especially in small, enclosed spaces.
Which air purifier tech can actually help with allergens?
Each air purifier technology has its pros and cons and is more effective against some types of pollutants than others. So, which types are best for allergens?
- HEPA: A HEPA filter is a fabric mesh designed to meet a U.S. Department of Energy standard for trapping particles. It is able to trap 99.97 percent of all particles down to 0.3 microns in diameter. Allergens are generally larger in size than 0.3 microns, so HEPA filters can be effective at removing allergens from the air. Portable HEPA air purifiers are proven to reduce allergens significantly enough to achieve reduced allergy symptoms, but only in the room where the purifier is used [Sublett]. The most significant benefits can be gained by using it overnight in the room where you are sleeping. HEPA filters will eventually become clogged with the particles they trap, and therefore must be replaced regularly. All in all, HEPA filters are an acceptable option for allergen control.
- PECO: PECO technology inside the Molekule air purifier has the ability to destroy allergens, removing them from the air, and has been used in a pilot study to measure impact on nose and eye symptoms. Because of the technology’s capability against the wide range of allergens, from pet dander, dust mites, pollen to mold, PECO is a good option.
- UV-C: These air purifiers use ultraviolet light to kill microbes that pass through it. While this is a proven technology, residential UV-C purifiers are unlikely to provide the intensity of light and time of exposure needed to effectively kill microbes. Plus, UV-C light creates a small amount of ozone, which is a negative side effect. At best, UV-C light might deactivate mold spores, but it will have no effect on other allergens.
Ineffective air purifier technology against allergens
These next few technologies are not very effective for allergies, and some listed here are not even designed to handle general allergy triggers.
- Carbon: Carbon, or activated charcoal filters, use “adsorption” to remove gaseous pollutants from the air. While they can be combined with other types of filters to create a hybrid design, the carbon filter itself has no ability to remove allergens from the air. They might reduce pet odor, however.
- Ozone generator: An ozone generator is an air purifier that produces ozone gas. While ozone gas has the ability to decontaminate rooms, it can only do so at high concentrations that are toxic to humans. The EPA sets health standards for ozone concentrations, and has found that some ozone generators produce ozone at high enough concentrations to violate those standards. Conversely, the EPA has also found that at lower concentrations, ozone has no effect on air quality. So an ozone generator is either doing absolutely nothing, or making you sick, neither of which will help you with your allergies.
- Electrostatic: An electrostatic air purifier works using the same basic process as an ionizer, but it also has a charged collector plate. The oppositely charged particles stick to the plate rather than falling all over the room. However, an electrostatic purifier’s efficiency drops drastically once the plate starts getting dirty, so it suffers from the same drawbacks as an ionizer.
An ionizing air purifier will, at best, temporarily remove allergens from the air, causing them to precipitate onto the carpet and furniture. They will likely get kicked back into the air again, so an ionizer is simply not effective for removing allergens or other particulate pollutants from the air. Look to other air purification technologies if you want to reduce your allergy symptoms.