NYC Approves 4,000 Classrooms With Unreliable Ventilation For In-Person Schooling

Thousands of New York City classrooms have been cleared as having adequate ventilation for safe, in-person instruction even though they do not meet the COVID-19 standards set by federal experts or recommended by building industry experts, WNYC/Gothamist has found.

A simple, green checkmark indicates whether “operational ventilation” is available in one of the 58,600 classrooms surveyed by the city’s Department of Education (DOE). As of August 29th, officials have awarded this seal of approval to 97% of these classrooms.

But the DOE classifies at least 4,000 of these approved classrooms as relying exclusively on functioning windows—a lower standard than what would be expected to prevent airborne transmission of the coronavirus indoors. If these window-only rooms lost their “operational” status, it would triple the number of classrooms currently ineligible for in-person learning this fall.

“Windows are not a reliable way for you to get outside air,” said Dr. Marwa Zaatari, a mechanical engineer and member of the Epidemic Task Force of the American Society of Heating and Air-Conditioning Engineers (ASHRAE), which is cited in Centers for Disease Control and Prevention recommendations for schools and other buildings. “Is it better than zero? Yes. But, as a ventilation engineer, can I predict how much [fresh] air you’re getting at each hour of the day? The answer is no.”

Ventilation, or the process of exchanging potentially contaminated indoor air with fresh air, is a key mitigation measure for preventing coronavirus transmission, alongside precautions like getting vaccinated, wearing masks and physically distancing (although the latter could be difficult to do in many of the city’s public schools). Well ventilated rooms have lower concentrations of airborne virus particles, reducing the risk that someone will become sick in that room.

As in-person learning returns to full capacity this fall, air quality has become a top concern of many parents thinking about the status of COVID protocols in schools.

When asked in a national Rand survey what measures needed to be in place to feel safe sending their children to school in person, parents most often picked ventilation in each classroom, with 71% saying it was important to them.

Last year, New York City tried to get ahead of such worries by conducting ventilation surveys across each of its public schools. But Zaatari and other ventilation experts are concerned that the city’s published results don’t provide sufficient information to determine whether a classroom actually meets established air quality standards. As WNYC/Gothamist reported this week, more than 1,500 classrooms are either in the midst of upgrades, which the Department of Education says are ongoing, or have been taken out of use.

The DOE website currently reads that “A room’s means of ventilation must be operating as designed to be cleared for occupancy. This could be through natural ventilation, mechanical ventilation, or a combination of those means.” Mechanical ventilation refers to a heating, ventilation and air conditioning (HVAC) system or a window air-conditioning unit. Open windows provide natural ventilation.

But as recently as July 3rd, the DOE called for “at least two” modes of ventilation for a classroom to be operable, noting that this standard could include a window that opens or an exhaust or supply fan.

When asked why the standard was rewritten and whether this new wording led to more classrooms being classified as operational without physically adding modes of ventilation, a DOE spokesperson said the only thing that had changed about the city’s approach over the past year was the addition of supplementary safety measures, such as carbon dioxide monitors for checking air quality, air purifiers and exhaust fans for windows.

“The DOE’s ventilation page was updated to reflect CDC guidelines and ensure that the condition of the classroom is accurately conveyed to parents,” the spokesperson said via email. “By ensuring the designed ventilation in the building is operable, the DOE is following the recommendations of health experts.”

The city has also invested in special MERV-13 filters, which can capture airborne particles such as viruses. But these filters and the air purifiers are not reflected in the DOE’s building ventilation surveys, making it unclear which classrooms will benefit.

Some critics say the funds used to fashion the latest improvements could have been spent more wisely, as one of the key air purifiers being installed in New York City schools doesn’t meet the best standards for filtration. And regardless of how many ventilation features a classroom has, a checkmark indicating their presence isn’t the same as measuring and clearly publishing how well they’re working on a day-to-day basis.

“We have standards that exist for a reason,” Zaatari said. “We know what is adequate.”

Measuring Success

The effectiveness of any ventilation system is measured in the air change rate, or the number of times indoor air is replaced with outdoor air each hour. Another option is filtered, recirculated air, which can also be combined with outdoor air to freshen a room.

ASHRAE recommends an air change rate of five to six times per hour for classrooms, although the figure could vary depending on the size of the space and the number of students. A report from the Harvard School of Public Health also called five to six air changes per hour in a classroom “excellent” and three to four “the bare minimum.”

Although the city’s education department hasn’t shared its target for air change rates inside its classrooms, a spokesperson said, “The DOE’s goal is to bring all buildings in line with the original ventilation design for the building and in alignment with both CDC and ASHRAE guidelines regarding ventilation standards.” Custodians will be given CO2 monitors to measure air quality and anemometers to gauge airflow, the spokesperson added.

When relying on windows, “You’re kind of at the whim of Mother Nature,” said Richard Corsi, dean of the Maseeh College of Engineering and Computer Science at Portland State University. “You could open a couple of windows in a classroom and increase the air exchange rate only by one air change per hour. But if it’s windy outside and the building is at the right orientation with respect to the wind, you might get five air changes per hour.”

The exterior of FDR High School in Brooklyn, featuring its windows and air conditioning units


Franklin Delano Roosevelt High School in Brooklyn, August 2021

Scott Heins / Gothamist

The exterior of FDR High School in Brooklyn, featuring its windows and air conditioning units


Klearview-supplied air conditioners in the windows of Franklin Delano Roosevelt High School in Brooklyn, August 2021

Scott Heins / Gothamist

To bolster air quality, the DOE is installing 110,000 MERV-13 filters in school buildings with central HVAC systems as well as window A/C units for individual classrooms. The latter is supplied by Klearview Appliance, a Brooklyn-based company that has signed 79 active contracts with the city since August 2020—worth a combined $1.9 million.

But not all classrooms are connected to their school’s cooling and heating systems nor equipped with window A/C units. Mayor Bill de Blasio pledged every New York City classroom would have air conditioning by 2022, but the DOE’s latest report card shows 12,000 rooms—about 20% across the city—still lacked access as of this January.

When asked directly, a DOE spokesperson wouldn’t clarify what percent of classrooms will be covered by MERV-13 filters. Both Zaatari and Corsi say these filters are highly effective and should be used wherever possible.

Did The City Spend $43 Million On Subpar Air Purifiers?

A teacher working at the Upper East Side’s Julia Richman Education Complex said she had concerns about being able to use the pair of portable purifiers the city is providing to each classroom to enhance air quality. The campus has one of the largest shares of classrooms among New York City’s school buildings that have failed to receive a green checkmark for ventilation. It ranks 15th, with 70% of its classrooms classified as non-operational.

“Due to old electrical [infrastructure], if you have a smart board on, a printer, and maybe charge your computer, you may cause an electrical outage for not just your room, but a few others,” the teacher, who asked for their name to be withheld given the sensitivity of the issue, said via email. “I wonder now with also having to keep two air purifiers on if that means I am not able to use the other necessities in my classroom.”

The engineers WNYC/Gothamist spoke with were also skeptical about the DOE’s choice of air purifiers but for a separate reason.

The exterior of Julia Richman Education Complex in Manhattan, featuring its windows and air conditioning units, on the Upper East Side.


Julia Richman Education Complex in Manhattan, August 2021

Scott Heins / Gothamist

Search for “air purifier” among the city’s database of municipal contracts, and you’ll find nine deals made since January 2020. Five contracts belong to the DOE and are currently committed to spreading $64 million across multiple suppliers.

The biggest recipient is Manhattan-based Delos Living, maker of the Intellipure air purifiers. Chalkbeat reported on August 18th that Delos advised the DOE to purchase two Intellipure air purifiers for each classroom.

In general, purifiers can provide a quick fix for improving air quality, said Zaatari, but the Intellipure model lacks HEPA filters, which are considered the industry standard for filtration. The CDC’s school guidance calls for portable air cleaners that use HEPA filters.

The exterior of Julia Richman Education Complex in Manhattan, featuring its windows and air conditioning units, on the Upper East Side.


Julia Richman Education Complex in Manhattan, August 2021

Scott Heins / Gothamist

“They paid a lot of money for it without a great return on investment in terms of reducing the risk,” Zaatari said. As of August 27th, the DOE has already spent $37 million on its Delos contracts, and it is committed to another $6.1 million. The department made its initial contract with the company a year ago for $2.7 million. The deal has grown over time, with a $21.7 million addendum coming as recently as April.

Corsi said purifiers without HEPA filters are “largely unproven, and that’s the kindest I could be.” An independent study of the effectiveness of the Intellipure devices by a team of researchers at the Illinois Institute of Technology found that it would rank ninth out of 12 products they’ve tested this year.

Zaatari estimated that in classrooms with only windows and Intellipure units, there would be about two air changes per hour—less than half of what would be considered safe by ASHRAE. Delos representatives provided DOE with the same estimate, Chalkbeat reported.

The exterior of Julia Richman Education Complex in Manhattan, featuring its windows and air conditioning units, on the Upper East Side.


Julia Richman Education Complex in Manhattan, August 2021

Scott Heins / Gothamist

In a recent report on school safety, the DOE claims that it has installed HEPA purifiers in each classroom, despite the fact that Intellipure units lack the filters. A spokesperson for DOE did not respond to a question about this apparent discrepancy—but echoed Delos’ claim that its purifiers exceed HEPA standards.

With the more contagious delta variant spreading, Corsi says proper ventilation is more important than ever for schools.

“This is an airborne infectious disease, right?” he said. “What matters is your inhalation dose.”

He cited mask-wearing as a crucial way to minimize the amount of virus someone could potentially inhale, particularly among younger children who can’t yet get vaccinated. But, he added, “With the delta variant being so infectious, it’s important to lower the dose even more.”

“I want to be at school”

First-grade teacher Sarah Allen says she is in one of the classrooms with a window but no mechanical ventilation at P.S. 372 in Brooklyn’s Park Slope neighborhood. Allen, whose students are too young to get vaccinated against COVID-19, said she was initially encouraged when her classroom received the air purifiers, even though they were pretty loud. But she said she became concerned when she started researching the brand the DOE chose.

“It’s funny because when I speak up about safety, a lot of parents are like, ‘You just want to stay home and sit on your computer,’” said Allen. “And I absolutely hated that. I want to be at school.”

Annie Tan, who teaches special education for fourth and fifth graders at a school in Brooklyn’s Sunset Park, says she is likely going back to the opposite situation: A basement classroom with mechanical ventilation but no windows.

Her room earned a green checkmark from DOE indicating that its ventilation system is working, but Tan says the lack of a window makes her nervous. She wishes she had more details about the air change rates or other quality measures.

The exterior of Julia Richman Education Complex in Manhattan, featuring its windows and air conditioning units, on the Upper East Side.


Julia Richman Education Complex in Manhattan, August 2021

Scott Heins / Gothamist

The DOE said that each school building’s custodian engineer performs a daily walkthrough, so the department’s online tracker is updated whenever they change the ventilation status of a room. Just within the past few days, between August 25th and 29th, 80 more classrooms became operational.

“Regardless of what combination of methods are used in each classroom, there are objective ways to measure the adequacy of ventilation. One is by measuring the CO2 concentration in rooms that are occupied. The other is by measuring air changes per hour,” the DOE spokesperson said. “DOE engineers are using both methods to ensure that whatever combination of approaches are used that they meet or exceed CDC recommendations.”

But given the specific changes and results aren’t outlined in the ventilation surveys, a teacher or parent has no idea what improvements occurred—and if enough was done to prevent airborne transmission of the coronavirus.

“I know that’s a lot to ask of our custodial engineers who are already completely overworked,” said Tan. But she said more information, including whether her classroom will have MERV-13 filters, would help put her mind at ease.

“I also have the trauma of March 2020 associated with that classroom,” she acknowledged, noting that several of her students had family members die of COVID-19 last year.

Other teachers have also spoken up about safety concerns since the DOE began publishing ventilation reports last year. In October, a group of 46 New York City public school teachers at nine schools spread across Queens, the Bronx and Manhattan filed a complaint with the state Department of Labor saying New York City was failing at its efforts to measure and report on classroom ventilation. The teachers, represented by two environmental legal nonprofits, said DOE was violating the Public Employee Safety and Health (PESH) Act and urged the state to intervene.

According to one of the lawyers for the teachers, the state’s Department of Labor initially said that the complaint didn’t fall under the jurisdiction of its PESH bureau. The teachers challenged that decision, and the state’s Industrial Board of Appeals ultimately ruled that the Labor Department had to at least respond to the complaint.

The Department finally issued a response in July saying, “Unfortunately, the specifics of your complaint do not meet the requirements and description of a safety and health hazard under NYS Code or Rules or under federal [Occupational Safety and Health Administration] standards.”

Jaclyn Jeffrey-Wilensky and Jessica Gould contributed to reporting.