Many U.S. schools were in dire need of upgrades — burdened by leaking pipes, mold, and antiquated heating systems — long before the covid-19 pandemic drew attention to the importance of indoor ventilation in reducing the spread of infectious disease.
The average U.S. school building is 50 years old, and many schools date back more than a century.
So, one might assume school districts across the nation would welcome the opportunity created by billions of dollars in federal covid-relief money available to upgrade heating and air-conditioning systems and improve air quality and filtration in K-12 schools.
But a report released this month from the Centers for Disease Control and Prevention found most U.S. public schools have made no major investments in improving indoor ventilation and filtration since the start of the pandemic. Instead, the most frequently reported strategies to improve airflow and reduce covid risk were notably low-budget, such as relocating classroom activities outdoors and opening windows and doors, if considered safe.
The CDC report, based on a representative sample of the nation’s public schools, found that fewer than 40% had replaced or upgraded their HVAC systems since the start of the pandemic. Even fewer were using high-efficiency particulate air, or HEPA, filters in classrooms (28%), or fans to increase the effectiveness of having windows open (37%).
Both the CDC and White House have stressed indoor ventilation as a potent weapon in the battle to contain covid. Congress has approved billions in funding for public and private schools that can be used for a broad range of covid-related responses — such as providing mental health services, face masks, air filters, new HVAC systems, or tutoring for kids who fell behind.
Among the sizable funding pots for upgrades: $13 billion for schools in the 2020 Coronavirus Aid, Relief, and Economic Security Act; an additional $54 billion approved in December 2020 for schools’ use; and $122 billion for schools from the 2021 American Rescue Plan.
“Improved ventilation helps reduce the spread of covid-19, as well as other infectious diseases such as influenza,” said Catherine Rasberry, branch chief of adolescent and school health at the CDC’s National Center for HIV, Viral Hepatitis, STD, and TB Prevention. “Investments made now can lead to lasting improvements in health.”
A wealth of data shows that improving ventilation in schools has benefits well beyond covid. Good indoor air quality is associated with improvements in math and reading; greater ability to focus; fewer symptoms of asthma and respiratory disease; and less absenteeism. Nearly 1 in 13 U.S. children have asthma, which leads to more missed school days than any other chronic illness.
“If you look at the research, it shows that a school’s literal climate — the heat, the mold, the humidity — directly affects learning,” said Phyllis Jordan, associate director of FutureEd, a think tank at Georgetown University’s McCourt School of Public Policy.
Clean-air advocates said the pandemic funding provides a once-in-a-generation opportunity to make the air more breathable for students and staff members with allergies and asthma, as well as helping schools in California and throughout the drought-stricken West weather the growing threat of smoke inhalation from wildfires.
“This is a huge deal for schools,” said Anisa Heming, director of the Center for Green Schools at the U.S. Green Building Council, a nonprofit that promotes ways to improve indoor air quality. “We haven’t had that amount of money coming from the federal government for school facilities for the last hundred years.”
Still, many school administrators aren’t aware that federal funding for ventilation improvements is available, according to a survey published in May by the Center for Green Schools. About a quarter of school officials said they did not have the resources to improve ventilation, while another quarter were “unsure” whether funding was available, according to the survey.
Even before covid spotlighted the issue of improving airflow, an estimated 36,000 schools needed to update or replace HVAC systems, according to a 2020 report from the Government Accountability Office.
Most schools don’t meet even minimum air quality standards, according to a 2021 report from the Lancet Covid-19 Commission. A pre-pandemic study of Texas schools found that nearly 90% had excessive levels of carbon dioxide, released when people exhale; high concentrations in the air can cause sleepiness, as well as impair concentration and memory.
Baltimore, Philadelphia, and Detroit — cities where many older buildings lack air conditioning — have all closed schools this spring due to excessive heat. And a year before the covid pandemic hit, schools in states including Alabama, Idaho, Michigan, Oklahoma, Tennessee, and Texas closed due to flu outbreaks.
Many schools have been slow to spend covid relief dollars because of the time-consuming process of hiring contractors and getting state or federal approval, said Jordan of FutureEd.
In the first year of the pandemic, many schools assigned custodial staff to wipe down surfaces frequently throughout the day. In Seattle, the district asked staffers to work overtime to help do that cleaning, said Ian Brown, a resource conservation specialist at Seattle Public Schools.
Some school officials say they feel pressured by parents to continue spending money on disposable wipes and surface cleaning, even though science has shown that the coronavirus spreads largely through the air, according to the Center for Green Schools’ report. Parents and teachers sometimes put more faith in conspicuous measures like these than in ventilation improvements that are harder to see.
And not all schools have spent federal funding wisely. A 2021 KHN investigation found that more than 2,000 schools across the country used pandemic relief funds to purchase air-purifying devices that use technology that’s been shown to be ineffective or a potential source of dangerous byproducts.
School districts are required to spend at least 20% of American Rescue Plan aid on academic recovery — such as summer school, instructional materials, and teacher salaries — leading some schools to prioritize those needs ahead of ventilation, Jordan said. But she noted that a FutureEd analysis of school district spending plans indicated districts intend to devote nearly $10 billion from the latest round of funding to ventilation and air filtration in coming years, budgeting about $400 a student.
Los Angeles schools, for example, have budgeted $50 million to provide 55,000 portable commercial-grade air cleaners for classroom use. Durham Public Schools in North Carolina is spending $26 million to update ventilation. Schools in St. Joseph, Missouri, plan to spend more than $20 million to replace aging HVAC systems.
In Boston, the school district has installed 4,000 air quality sensors in classrooms and offices that can be monitored remotely, allowing facilities managers to respond quickly when ventilation suffers.
Albemarle County Public Schools in Virginia, meanwhile, purchased “medical-grade” air purifiers for isolation rooms in school nurse offices, where children with covid symptoms wait for pickup. These units are equipped with HEPA filtration and interior ultraviolet light to kill germs, and are powerful enough to clean all the air in the isolation rooms every three minutes.
But workable solutions don’t have to be high-tech.
Seattle Public Schools used relatively inexpensive hand-held sensors to assess air quality in every classroom, Brown said. The district then purchased portable air cleaners for classrooms with inadequate ventilation rates.
While replacing a central air system is a major construction project that can easily top $1 million per school, quality HEPA purifiers — which have proven effective at removing the coronavirus from the air — run closer to $300 to $400.
About 70% of schools have at least inspected their heating and ventilation systems since the pandemic emerged, a key first step to making repairs, according to the CDC.
Engineers in Ann Arbor, Michigan, have inspected “every piece of mechanical ventilation in the school district, opening up every unit and inspecting the fans and pumps and dampers to make sure they’re operating properly,” said Emile Lauzzana, executive director of capital projects for Ann Arbor Public Schools.
“That’s just something that school districts don’t normally have the funds to do a deep dive on,” Lauzzana said. “It’s unfortunate that it took a pandemic to get us here, but we’re in a much better place with indoor air quality today.”