What Does an Ionizer Do on a HEPA Filter? A Comprehensive Guide

Ionizers, also known as negative ion generators, are devices that create a static charge around airborne pollutants that float around the room. This charge causes the particles, such as dust, allergens, and pet dander, to stick to the closest surface they can find. In some cases, these devices contain a collector to attract charged particles back to the unit. Ionizers don't require you to change the filter, so they're easier to maintain if you don't mind dusting or vacuuming regularly to clean up particles that fall on the floor.

They also purify a larger area than HEPA air purifiers and can remove smaller particles from the air. However, an ionizer without a fan doesn't circulate air as quickly, so it could take longer to purify a room. High-efficiency HEPA particulate filters in air purifiers are more limited than ionizers because they cannot remove the smallest particles, but they do remove 99.97% of dust, allergens, and microorganisms from the air that contribute to respiratory problems. Abrasion can cause these particles to be resuspended in the air.

Decades later, British electrical engineer Cecil Alfred “Coppy” Laws developed the first air ionizer for domestic use. The concept of air ionizers has been around since the beginning of the 20th century. It was first studied by scientist Alexander Chizhevsky who researched aeroionization in biology. Instead of filtering these particles out of the air, an ionizer makes them too heavy to remain suspended in the air. Ionizers don't have filters because they emit electrically charged particles to remove pollutants from the air.

The load created by an ionizer allows a HEPA filter to capture more particles. Knowing the difference between an ionizer and an air purifier can help you find the right solution for your family. Daniel Tranter, indoor air unit supervisor at the Minnesota Department of Health, recommends that an ionizer meet the UL 867 standard certification for electrostatic air filters or, preferably, the UL 2998 standard certification for zero ozone emissions. Ionizers come in different shapes and sizes and are usually small enough to fit in your hand.

Ionizer air purifiers are often marketed under various names such as “ion air purifiers”, “negative ion air purifiers”, “air ionizers” and “bipolar needle-tip ionization”. Most major air purifier companies use ionizers in their air purifiers, including Xiaomi, Blueair, Levoit, and many more. A summary of scientific testing of air purifiers revealed that most air ionizers have no notable effect on particulate matter levels. Unlike many purifier companies, Smart Air does not use ionizers in its purifiers to achieve its high CADR rates; only safe and effective HEPA filters are used.

So do popular ionizing air purifiers such as Ionic Pro and Clarifion work? Decades later British electrical engineer Cecil Alfred “Coppy” Laws developed the first air ionizer for domestic use. The concept originated in the work of scientist Alexander Chizhevsky who studied aeroionization in biology.

Nancy Pickell
Nancy Pickell

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