Philly schools are spending $4.5 million on air purifiers to curb COVID-19. They won’t help much, experts say.

Philadelphia school officials are planning to consult with more air quality scientists after meeting Monday with an expert critical of the district’s $4.5 million purchase of NASA-originated air purifier technology. The expert, a Drexel professor, said the purifiers were ineffective at reducing the spread of coronavirus and had the potential to create harmful chemicals.

Preparing to welcome students in-person for the first time since the onset of the pandemic, district officials last week touted the multimillion dollar investment in air purifiers advertised to rid both air and surfaces of SARS-CoV-2, the novel coronavirus that causes COVID-19.

The devices have already been purchased and will be installed in every classroom by the end of July, a district spokesperson said.

But following the School District’s announcement, several experts questioned the purifiers’ effectiveness and safety. They included Michael Waring — professor of indoor air quality and department head of civil, architectural, and environmental engineering at Drexel University — who met with School District Chief Operating Officer Reggie McNeil on Monday.

According to a spokesperson, the district used federal funding to purchase more than 9,500 devices for its 200-plus buildings. They use ActivePure Technology, which, according to its website, protects against the coronavirus by pulling free oxygen and water molecules through a “patented honeycomb matrix” that oxidizes molecules that are then released back into a room to neutralize viruses.

Boasting origins at the NASA Space Station, the company’s site says FDA-compliant testing shows its units reduce more than 99.9% of airborne viruses, including coronavirus, within three minutes.

» READ MORE: Philly schools to install air purifiers in every classroom and plan to require masks for in-person learning this fall

In selecting the purifiers, the School District “did thorough research and consulted with the ActivePure team,” the spokesperson said. “Based on its technology, which has been extensively tested and proven to be safe and effective, the decision was made to proceed with purchasing the ActivePure devices.”

It was not apparent, though, who had done the vetting.

ActivePure, which employs former Trump adviser Dr. Deborah Birx as its chief medical and science adviser, says it “does not replace the need to follow CDC guidance and should be used as a complementary technology.”

But the purifiers are ineffective at best and harmful at worst, said Waring.

The ionization tech touted by ActivePure to kill coronavirus particles, he said, produces charged molecules that can latch on to virus particles in a lab setting. But in a real-life classroom, he said, they can combine with other organic compounds in the air, potentially creating chemicals dangerous to human health.

The EPA, too, has cautioned that air ionization “is an emerging technology … and little research is available that evaluates it outside of lab conditions.”

In Philadelphia and beyond, the technology has been marketed to help schools remove coronavirus. But it has also been scrutinized. A report in May by Kaiser Health News found that as kids return to in-person learning and districts receive an influx of federal funds for safety and improvements, schools throughout the country are paying big money — and, academic experts say, often “lulled into a false sense of security” — by air-purifying technologies promising to combat COVID in classrooms.

While the Centers for Disease Control and Prevention has said that high-efficiency particulate air filters are some of the most efficient at capturing human-generated virus particles, Waring said that according to ActivePure specs, the fans in the classroom purifiers are too small to properly circulate and filter the air of a 600-foot classroom.

“Think if you’re trying to cool a really large living room in a house and you go buy the smallest air conditioner from the store,” he said. “It’s just not going to work … because it doesn’t move enough air through and it doesn’t have enough capacity. An air cleaner is the same way.”

Much cheaper filtering units with larger airflow but no ionization technology — or even the district’s previous hotly contested, low-tech ventilation solution, window fans — would have been a more effective and affordable route, Waring said. Still, more than one new purifier, without its ionization component, could be used in a room to work more effectively, he said, and opening windows can also help with airflow.

“I think they’ve probably way overspent what they needed to spend to get that small amount of filtration,” he said.

Ventilation in Philadelphia’s classrooms was a prior point of contention between the teachers union and district.

Arthur Steinberg, director of the Philadelphia Federation of Teachers’ Health and Welfare Fund, said he believed the purifiers were “safe to use — they’re not a substitute for outside air, but they enhance what you have. They’re not harmful. If it turns out that information is inaccurate, I would expect the district to take appropriate action.”

PFT officials have publicly supported a full return to in-person education, a marked shift from the union’s position earlier in the year, when leaders urged members not to return to buildings due to concerns over COVID-19 case counts and environmental conditions inside schools.

» READ MORE: ‘We’re forever changed’: Schools share challenges and lessons from the pandemic

The school system has a stock of aging buildings and a history of problems managing them, including widespread problems with asbestos and lead paint.

Jerry Roseman, the PFT’s longtime director of environmental science, said that any mitigation strategy is “a good thing,” but has not been given specifics on the purifier models and is wary of the district’s claims about what they will accomplish.

“Whether air purifiers are used or not, there needs to be real ventilation upgrades, and it needs to get vetted by people other than the district,” said Roseman.

The district used some air purifiers in the spring, in rooms that had no mechanical ventilation or other issues, and the PFT signed off on the purifiers in that limited context then. The district did not consult the union on the latest rollout.

Abby Rudolph, an associate professor in Temple’s College of Public Health, said she agrees with EPA advice that an air filter alone does not provide adequate protection against the coronavirus. But, she said, portable air purifiers can be part of a larger plan. The risk can be further reduced when they are used in conjunction with physical distancing, masks, and hand washing, she said.

Following guidance from the city’s Health Department, the Philadelphia School District is planning to require masks, and officials said that hand-washing supplies and sanitizing stations will be made available.

Still, Waring said, if the district’s ventilation plan remains as is, he plans to send his son, a rising junior at Central High School, back to school in the fall.

“It’s a little bit of an easier decision because he’s older and vaccinated,” he said. “Who I worry about are the unvaccinated young children.”