It may all seem like a blurry memory now, but at one point in just the past three years, air quality was the biggest topic on the planet when it came to the workplace (or any place). Remember, there were still a lot of unknowns about how the Coronavirus was spread. Masks were mandatory, and thus, ridding indoor air of pathogens became the top priority.
As the pandemic churned along and vaccines became a reality, getting workers back in the office was a big goal for cities, as many downtown areas struggled without the foot traffic from nearby offices. But to actually get people to come back to the office, buildings had to prove that there would need to be serious efforts to improve air quality and keep everyone safe. In response, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) revised and updated standards related to indoor air quality, adding more stringent requirements and expanding its focus on other building systems (like equipment, filtration, and controls) that also contribute to indoor air quality. All the attention on indoor air quality (we started calling it “IAQ”) led to a number of new companies entering the space that touted innovations that killed or filtered viruses and germs from the air.
The pandemic certainly supercharged the focus on IAQ, but it was already a growing concern in the commercial real estate industry in the years leading up to the global health crisis. Now, surveys are showing that a large majority of office workers are still worried about the air quality in their workplaces. A big initiative by the Biden Administration is asking building owners to upgrade HVAC systems to improve air quality in their properties. But understanding the best way to ventilate and filter indoor air still isn’t entirely clear.
One of the innovations in air quality to emerge as a tool for office buildings was the air cleaning technology bipolar ionization (BPI), which works by emitting positively charged ions into the air that then attach themselves to pollutants and bacteria, which can then cause the degradation of microorganisms, break up chemicals, and make larger particles stick together (potentially making them easier to filter). This type of air cleaning technology has become more popular in office buildings after the pandemic led to a surge of interest in air filtration systems.
While the technology has been around for at least a decade, mostly in healthcare settings, more building owners are choosing to use BPI in their properties. Notable office buildings that have installed BPI systems include Manhattan’s Empire State Building, which partnered with the Connecticut-based company AtmosAir to bring BPI to the iconic property. In this case, the tech was an add-on to existing HVAC equipment and was deployed across the whole building. Not far from Empire State Realty Trust’s trophy tower, SL Green’s One Vanderbilt skyscraper has also been outfitted with BPI technology. One Vanderbilt’s landlord partnered with provider WellAir to install devices across office floors, the building’s observation deck SUMMIT One Vanderbilt, and tenant and public spaces like the lobby, transit hall, and amenity floor. “We value the health and safety of our tenants and recognize that indoor air quality is crucial for both companies and their employees as they return to the office,” said SL Green CEO Edward Piccinich after the installation last year.
While it’s growing in popularity, especially with some major office landlords, BPI is not yet a widespread technology in the commercial building sector. Historically, BPI has been used far more in water than in air. It’s been a mainstay of water purification, especially in water treatment, where it’s been used extensively. At data centers, where cooling is hugely important, properties use vast amounts of chilled water to keep temperatures cool and prevent any servers from overheating and failing, or even worse, causing a fire. That water needs to be treated, but treating it with chemicals can be expensive and corrosive. In this function, BPI balances the Ph of water in cooling towers.
BPI has been embraced by more office owners, with several touting it as a kind of “secret weapon” against the Coronavirus. However, the technology has also been heavily criticized. A federal lawsuit filed in 2021 against a maker of BPI technology not only claims that the systems don’t do what the company claims they will, it actually makes the air quality worse. In the lawsuit, the plaintiffs argue that the company’s claims about its products’ ability to kill COVID-19 are based on unvalidated testing methods that don’t accurately reflect conditions in real life. The heart of the lawsuit surrounds the company’s advertisements of its products, which the plaintiff claims are “false and misleading.” The BPI method creates positively charged ions using high-voltage devices. Depending on the manufacturer, if a device’s voltage is high enough, it can produce ozone, which is harmful to the environment.
According to William Bahnfleth, Professor of Architectural Engineering at Penn State University, the big questions surrounding BPI are how well they work and whether we know that they’re safe. Bahnfleth has done extensive research on HVAC systems and indoor air quality and is one of the leaders at ASHRAE, where he served as president from 2013 to 2014. He was also the chair of the Epidemic Task Force between 2020 and 2022, throughout the height of the pandemic. While the benefits of bipolar ionization have been identified—ASHRAE once described it as “like Purell for the air and surfaces”—along with other additive air cleaners like hydrogen peroxide gas and hydroxyl radicals, there hasn’t been a lot of independent evidence that shows it’s effectiveness or that there are no adverse health effects.
In one lab research study by Trane, one of the largest air conditioning manufacturers in the world, researchers tested ionizers under a number of different conditions, specifically needlepoint BPI, which showed some effect on the concentration of viruses in the air but showed very little impact on surface growth. In needlepoint BPI, negative and positive ions are created by applying electricity to a tube with two electrodes, which then react with water vapor and oxygen in the air to create free radicals, which then can eliminate microorganisms and break down odors.
The global aerospace company Boeing was at one point considering using BPI technology in its aircraft and undertook a study on the effectiveness of the tech. In its research study, which was cited in the federal lawsuit, researchers found that it didn’t work well enough to adopt it at the time. At the same time, other published studies found that the ions do react with things in the air and produce a certain amount of particulate matter and gas-phase chemicals. “To characterize the current state of knowledge, it just isn’t very clear,” Bahnfleth told me. “We don’t have a good way to evaluate whether air cleaners are as effective as claimed and safe for use, but there are a number of standards under development now to help.”
While there isn’t much research into BPI and other kinds of air cleaners at this time, Bahnfleth is optimistic that more research will happen, given the recent federal funding for improving air quality. That’s good news for everyone because a ton of different products that use some kind of BPI technology are now available. But given the conflicting reports over how effective the tech is at improving indoor air quality—and even claims that it worsens air quality—it’s unclear whether the promise of BPI lives up to reality.
