A study from a collaboration of researchers at Illinois Tech, Portland State University, and Colorado State University has found that air purifiers, despite their recent boom during the pandemic, may exchange some bad chemicals for some equally bad chemicals. The study, published in the journal Building and Environment, investigates the unintended consequences of air purifiers.
Air purifiers are meant to filter the air from volatile organic compounds (VOCs), pollutants that have been linked to adverse health effects such as eye, nose and throat irritation, headaches, loss of coordination and nausea, and liver, kidney and central nervous system damage. The EPA reports that exposure to VOCs has even been linked to some cancer. But, according to this new study, air purifiers, while efficient at reducing some VOCs like xylenes, actually increase others, such as oxygenated VOCs and toluene.
The surge of air purifiers on the market, largely due to the pandemic, has given way to new interest in understanding how the various technologies work. After a comprehensive review of available technologies, the new study reports that the air purifier marketplace is host to inadequate test standards, confusing terminology, and a lack of peer-reviewed studies of their effectiveness and safety. This is particularly true for ion-generating systems, such as “bipolar ionization” devices.
"Manufacturers and third-party test labs commonly demonstrate their product's effectiveness using chamber tests, but these test reports often don't use experimental conditions that could show how the device actually performs in real-world conditions," said Brent Stephens, Chair of the Department of Civil, Architectural, and Environmental Engineering at Illinois Tech. "To the extent that there are testing standards for ionization and other devices, those are largely industry-led standards that remain underdeveloped at this point, focused mostly on ensuring just one pollutant, ozone, is not generated during operation."
Another concern are the potential chemical byproducts that could come out of the mixing of ion additives with other compounds in the air. Several known harmful byproducts are formaldehyde and ozone, but the researchers warn that without proper checkpoints, new particles may also be forming without our awareness.
"We should have a much better understanding of these effects before widespread use of these types of devices," said co-lead author Delphine Farmer. Stephens adds: "Without peer-reviewed research into the health impacts of these devices, we risk substituting one harmful agent for another. We urge others to follow guidance from organizations like the U.S. EPA and ASHRAE, 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."