Air Purifier vs Ionizer: What’s the Difference?

You might not be aware, but everything from our pets to cooking in our homes produces particles that pollute the air we breathe. A report from the Environmental Protection Agency (EPA) revealed that the concentration of some pollutants can be as much as two to five times higher in our homes compared to outdoors.

There are health ramifications related to poor indoor air quality, especially for those with respiratory conditions such as asthma, not least because we spend so much time inside. So what are the solutions? Use an air-quality monitor to find out which particulates are in the air, then consider introducing some tech. Devices such as air purifiers and air ionizers both claim to clean the environment indoors by removing or neutralizing the pollution particles in the air. We asked an expert from the EPA for his views on their effectiveness.

What does an air purifier do?

An air purifier uses filters to remove pollutants from the air. It works by drawing in air, which then passes through a range of different filters to remove various particles, circulating clean air back into the space.

A preliminary filter will remove larger particles such as pet dander and lint; the HEPA filter will extract air pollutants such as dust, bacteria and pollen; while the activated carbon filter is designed to remove volatile organic compounds (VOCs) – chemicals from cleaning sprays or frying foods, for example – out of our air. The air purifier then releases cleaned air back into the room. Note that filters have to be replaced at regular intervals to ensure efficiency, but the length of time between changes will vary between models.

What does an air ionizer do?

An air ionizer releases ions, or charged atoms/groups of atoms, into the air. A bipolar ionizer releases negative and positive ions, but the majority of ionizers release negative ions, which attach to positive ions – the tiny particles in cigarette smoke, for example – and cause them to clump together. These particles then land on surfaces from where they can be cleaned. However, an ionizer isn’t effective against larger particles such as dust or pet dander.

When ions charge other particles, a gas called ozone is produced. A 2020 scientific study claimed that ozone was effective at deactivating viruses, whether on surfaces or in the air. Other studies have claimed that an ionizer can help to decrease stress, help sleeping, and improve moods.

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What does our expert say?

Remmington Belford is a spokesperson from the EPA and argues that there’s a lot more scientific evidence for the effectiveness of air purifiers than ionizers. He explains: “There is much less information about the effectiveness of devices that use different technologies, such as ionization.”

He continues: “In addition, there are concerns that alternative technologies may change the chemical composition of the air and result in unintended exposures to potentially harmful byproducts, including ozone. Some devices may have greater potential to release these byproducts into the air than others, depending on the specific engineering of each device.”

The EPA has determined that bipolar ionizing is “an emerging technology” and therefore lacking the same controls as more established technologies. Belford explains: “Widely accepted standards such as the ANSI/AHAM Clean Air Delivery Rate (CADR) can help consumers compare how well different air cleaners remove particles from the air. Unfortunately, there are currently no standards to completely assess the safety of air cleaning devices.

“If consumers decide to use a device that incorporates ionization technology, the EPA recommends choosing one that meets UL 2998 standard certification (Environmental Claim Validation Procedure (ECVP) for Zero Ozone Emissions from Air Cleaners). The UL 2998 certification identifies devices that produce little or no ozone, but doesn’t provide information about other byproducts.”

The EPA has also released reports on ozone and states in one that, “when inhaled, ozone can damage the lungs. Relatively low amounts can cause chest pain, coughing, shortness of breath and throat irritation. Ozone may also worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections.”

An added disadvantage is that ionizers will not remove volatile organic compounds (VOCs) from the air. These include the odours and gases released from the paints we use on our walls and from some cleaning products.

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Which is the better option?

Evidence suggests that an ionizer is effective at removing some pollutants from the air in our homes, but nevertheless, it remains a less researched technology than the filter technologies used in air purifiers. However, the EPA is categorical in its concern about ozone production and this is a big red flag with regards to some ionizers. By contrast, research about HEPA filters is varied and vast – which, for now, suggests that air purifiers remain the go-to technology for cleaning indoor air.

To choose an air purifier, you need to consider the size of the area in which you wish the machine to work. You can use the CADR, which measures the effectiveness, to compare different models, as well as considering the initial cost and running costs thereafter, which will include replacement filters. And don’t forget to pay attention to the noise of the machine when it’s running, too.

Having cleaner air in your home brings huge health benefits, from combating allergies to alleviating symptoms for those suffering from respiratory issues. While air ionizers are a compelling offering, air purifiers are better regulated, with decades of research supporting their effectiveness at tackling household air pollution.