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One type of air purifier may not live up to its claims: study

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Chicago — Although a growing number of employers are purchasing air purifiers as part of reopening their workplaces amid the COVID-19 pandemic, one type of the technology might not be as effective as advertised, results of a recent study show.

Researchers from three universities conducted a series of experiments involving commercially available bipolar ionization devices. One set of experiments took place in a laboratory at the Illinois Institute of Technology, while the other involved a field test in a city in eastern Oregon. The researchers tested the effectiveness of the devices’ particle and gas removal capabilities, along with the “potential for byproduct formation.” They didn’t test the devices’ ability to remove germs or other pathogens.

According to an IIT press release, the researchers brought into the lab personal belongings, furniture and even old dissertations to create volatile organic compounds, which bipolar ionization air purifiers are designed to target. The Environmental Protection Agency says VOCs can cause eye, throat and nose irritation; headaches; loss of coordination; nausea; and liver, kidney or central nervous system damage, among other health effects.

Results show that the air purifiers didn’t reduce the level of particles less than 2.5 micrometers in diameter, also known as the PM2.5 level. A Colorado State University press release notes that PM2.5 particles “pose the greatest risk to health, as they can get deep into your lungs and some may even get into your bloodstream.”

Both releases note that few regulations governing air purifiers exist and the marketplace is “fraught with” inadequate test standards, few peer-reviewed studies for effectiveness and safety, and confusing terminology. Additionally, manufacturers’ claims aren’t usually verified independently.


“Without peer-reviewed research into the health impacts of these devices, we risk substituting one harmful agent for another,” study co-author Brent Stephens, chair of the Department of Civil, Architectural and Environmental Engineering at IIT, said in the CSU release. “We urge others to follow guidance from organizations like the U.S. EPA and [the American Society of Heating, Refrigerating and Air-Conditioning Engineers], which generally recommend the use of established, evidence-based measures to clean indoor air, including high-efficiency particle filtration and enhanced ventilation, in addition to face coverings and physical distancing, to help reduce airborne transmission of COVID-19.”

The study was published in the journal Building and Environment.

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