Can air filtration stop coronavirus at a Trump rally in Phoenix? Experts doubt it

The Dream City Church in Phoenix, where President Donald Trump is scheduled to attend a rally Tuesday, made a surprising claim Sunday: Its building has an air filtration system that can neutralize the coronavirus. Many experts found this startling, because there is little evidence such systems can stop the spread of the virus.

The claim came in a video in which the senior pastor, Luke Barnett, and Chief Operations Officer Brendon Zastrow discussed the presidential visit and the air purification system from a local company, IONaer, which echoes the claim of its system’s effect on the virus on its website. IONaer does business as CleanAir EXP.

"It was a technology developed by some members of our church," Zastrow said. "And we've installed these units. And it kills 99 percent of COVID within 10 minutes."

It's the kind of claim that has little basis in reality, experts say. Both the ionization technology on which the system is based, as well as the way it works, are of limited effectiveness.

"When it comes to COVID-19 transmission, person-to-person transmission between those within 6 feet of each other is driving the majority of transmission," Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security, said. "Any 'air cleaning' type of device would not be able to have an impact on this close range transmission and the video could give attendees a false sense of security.”

The videos with the claim about the air purification system have since been removed from the church's social media accounts.

Tim Bender, the CEO and co-founder of IONaer, which makes the air purification systems, stressed that they had only been tested on "surrogates," which are viruses similar to the coronavirus.

IONaer's CleanAir EXP published Tuesday the results of the third-party testing of its system that used "airborne coronavirus test surrogates," which are viruses similar but not identical to the SARS-CoV-2 virus that causes COVID-19. The study found that it was able to eliminate 99.9 percent of the coronavirus surrogates in air that passed through its system.

Bender also clarified that the system is ineffective if people come into close contact with one another.

"There is nothing we can do with someone who coughs or sneezes," Bender said. "The words we try to use is we add an additional layer of protection from passing viruses and bacteria through the area inside buildings. It’s just an additional layer of protection. If you’re taking the particulates out, you’re taking away the magic carpet that they’re traveling on."

Bender said that the company had reached out to the Food and Drug Administration about the system but had not heard back.

Building managers and events organizers face a particular challenge in dealing with the coronavirus. As scientists learn more about how the virus spreads, they've begun to focus on indoor environments in which people are often in close quarters.

The problem comes from tiny droplets that contain viral particles that are expelled when people speak, cough or sneeze. These droplets can hang in the air and end up infecting other people nearby. And this can happen quickly. So-called super-spreader events, in which one person can infect many others, have become a major focus for scientists trying to understand how the virus spreads.

Three studies published by the Centers for Disease Control and Prevention since late April examined coronavirus transmissions in such settings: a restaurant in Guangzhou, China, a call center in Seoul, South Korea, and a choir practice in Washington state. In each of the reports, scientists found that interactions in confined spaces — including talking and singing — likely contributed to outbreaks among people who were present.

The Dream City Church did not respond to an email and a voicemail requesting comment.

Trump is scheduled to begin a trip through Arizona on Tuesday, putting him in the middle of a state that is dealing with one of the worst outbreaks of the coronavirus. He will visit the church Tuesday afternoon, with organizers expecting about 3,000 attendees, according to The Arizona Republic.

Experts and even scientists in Trump's own administration have warned against such events.

Air purification systems, like the one cited by officials at the Dream City Church, would likely do little to protect people from catching the virus from close interactions indoors, according to L. James Lo, an assistant professor of civil, architectural and environmental engineering at Drexel University.

“The system will clean the air only when it was passing through the purifier, which means it helps very little in terms of person-to-person localized virus transmission,” Lo said.

If a person is sitting next to someone who has COVID-19 and is generating so-called aerosols by talking or coughing, “and you are there for [an] extended period of time, you will still likely get infected,” he said.

The National Air Filtration Association did not respond to a request for an interview, but its website states that filtration systems "can be a part of an overall risk mitigation approach but is not generally regarded as a solution by itself. There is no direct scientific evidence of benefit, but some reduced exposure can reasonably be inferred based on the ability of some filters to remove particles that contain a SARS-CoV-2 virus."

Air ionizers work by altering the chemical composition of particles in the air — some using high voltages and others by producing ozone. The idea is that by changing these properties, the systems can filter out potential allergens and other airborne particles.

Although the technology is not new, its effectiveness has been controversial, said William Bahnfleth, a professor of architectural engineering at Penn State University.

“Much of the proof of their performance is in the form of laboratory studies commissioned by manufacturers that are often performed under conditions that are not representative of actual application conditions,” he said in an email. “Many in the scientific community are skeptical.”