It affects every child in every school every second of the day.
It’s more important than the books they read, the problems they solve, the test scores they make, even the food they eat.
It’s the indoor air they breathe. School-age children take a breath 18 to 30 times every minute, adolescents 12 to 18 times every minute.
How warm or cold, dry or humid is the air they breathe? What allergens, pathogens, toxins or other airborne contaminants are they breathing in?
Studies show that poor indoor air quality hurts the health, academic performance, behavior and morale of students and teachers. And yet there are no federal laws or regulations that govern indoor air quality in schools, not even in a pandemic.
“There’s 20 different approaches, and 20 different depths of efficacy,” the Lancet’s COVID-19 Commission reported last April. “Nobody knows what to trust.”
Indoor air regs vary
Some states, including Mississippi, require school districts to inspect and monitor air quality in schools, but most do not.
Tennessee law “encourages” but does not require school districts to inspect or evaluate the air inside school buildings. A 2017 bill sponsored by Rep. Dwayne Thompson (D-Memphis) that would have required it never got out of committee.
Some state and local health departments inspect air quality in schools, but not in Tennessee.
Meanwhile, school districts here and across the country are spending billions of dollars in federal pandemic relief funds, in part to help schools “identify facility improvements to reduce the risk of COVID transmission and improve indoor air, quality, according to the Elementary and Secondary School Emergency Relief Fund.
Memphis-Shelby County Schools are spending about $120 million to replace aging heating, ventilating and air conditioning (HVAC) systems in 29 schools. The district also spent $25 million last year to install an unproven and controversial air-cleaning technology called bipolar ionization in all its schools.
But requirements, standards, and performance levels for HVAC systems vary from state to state, from district to district, even from school to school.
State and local building codes impose minimum standards for HVAC installation and repair. But some of those standards, set decades ago, impair the flow of fresh air in schools. Since 1973, federal regulations have cut by two-thirds the amount of fresh outdoor air mixed into HVAC systems to conserve energy and cut costs.
‘Little guidance’ given
Districts have been given “little guidance to inform their decisions about air quality measures,” according to a 2021 survey of 4,214 schools across the country by ASHRAE (the American Society of Heating, Refrigerating and Air-Conditioning Engineers) and the U.S. Green Schools Council.
Instead, school districts rely on varying, and at times conflicting, guidelines and recommendations from various government agencies, professional organizations, and nonprofits — including the CDC and EPA, and ASHRAE.
For the most part, school districts are trusting their own facilities managers as well as outside consultants and vendors.
“Without a statewide school indoor air quality (IAQ) policy — and an effective state program to implement the policy — the environmental health conditions in schools will vary from one school district to another, creating inequities that may result partly from differences in resources available to the schools,” reports the Environmental Law Institute.
“These differences in environmental quality can translate into differences in student and staff productivity, health and well-being.”
A life indoors
Most people spend about 90% of their time indoors, where levels of airborne contaminants may be five to 100 times higher than outdoor levels.
Schools are especially vulnerable.
Nearly 55 million people (about 16% of the U.S. population) spend many of their days inside elementary and secondary schools.
A typical school has four times as many occupants per square foot as a typical office building.
Students and adults carry contaminants such as allergens and communicable diseases into schools and propel them into the air every time they cough, sneeze, shout, talk, sing, laugh or cry.
Dry-erase markers, science lab chemicals, cleaning supplies, and school buses also emit pollutants into the air.
Poor indoor air quality can aggravate asthma and other respiratory illnesses, especially in children.
Nearly one in 13 school-age children suffers from asthma, the leading cause of school absenteeism due to chronic illness. Asthma is even more prevalent among children in poverty, children in the South, and Black children.
Before COVID-19, asthma was the most prevalent diagnosis at Le Bonheur Children’s Hospital.
“When kids go back to school, they’re just exposed to so much more, we always see a spike in asthma cases,” said Dr. Christie Michael, an allergist at Le Bonheur and associate professor at UT’s Health Science Center.
Rise of COVID-19
The spike in asthma cases was nothing compared to the spike in COVID-19 cases.
Last August, for example, Le Bonheur saw 226 emergency department visits and hospitalizations for asthma, and 881 for COVID-19.
In 2021, emergency department visits for asthma were up 32% last year, rising from 1,709 in 2020 to 2,504 last year. There were 2,226 emergency visits for COVID-19 last year.
Studies show that children with severe or poorly controlled asthma are up to five times more likely to be hospitalized with COVID.
Studies also show the benefits of improving indoor air quality in schools.
“In addition to decreased airborne infectious disease transmission,” the Lancet, a peer-reviewed medical journal, research shows that ventilation and air cleaning improvements are likely to lead to improved academic performance (in particular, reading and math performance), fewer missed school days for students, higher scores on cognitive function tests, and many benefits for teachers including decreased respiratory symptoms, increased teacher retention, and improved morale.”
How HVACs work
Conditioned air isn’t just heated, cooled, and dehumidified. It’s also ventilated and filtered.
Experts agree that ventilation and filtration are the most effective and efficient ways to remove contaminants from indoor air.
That’s a problem in many schools.
Outdated or poorly functioning HVAC systems are by far the most common infrastructure problem in schools.
A government study released last summer reported that 36,000 schools had HVAC systems that were outdated, or in need of repair or replacement.
“Many Kindergarten through 12th grade (K-12) schools in the United States do not have good ventilation,” the Bloomberg School of Public Health at Johns Hopkins University reported. “During the COVID-19 pandemic, it is even more important that ventilation problems in K-12 schools be addressed now. Along with other mitigation measures, improvements in ventilation in K-12 schools can decrease the risk of SARS-CoV-2 spread.”
In August 2020, after the pandemic’s first wave, the CDC said schools should “increase the delivery of clean air and dilute potential contaminants in the school.”
Open windows an issue
The agency recommended opening windows, using fans to exhaust indoor air and bring in fresh outdoor air, and improving ventilation and air filtration systems.
“Set HVAC systems to bring in as much outdoor air as your system will safely allow. Reduce or eliminate HVAC air recirculation, when practical and with expert HVAC consultation,” the CDC said.
HVAC systems mechanically ventilate air by mixing fresh outdoor air with recirculated indoor air.
The process can be aided with open windows and fans or hindered when air ducts are inadvertently blocked.
But opening windows is rarely an option in many schools and climates.
In older buildings, many windows no longer work. In newer buildings, many windows don’t open. In some grades, and in multi-story buildings, opening windows can be a safety hazard.
“We allow windows to be open when that’s not a safety issue,” said Genard Phillips, chief of business operations for MSCS. “But in our climate, it’s often either too hot and humid or too cold to open windows in a classroom. That also puts an extra strain on HVAC systems.”
Most schools use HVAC systems to ventilate the air, but many systems were designed for bare minimum ventilation standards set decades ago.
Ventilation is measured and monitored in “air exchanges,” or how many times the air volume in a space or room is supplied with outdoor air.
Harvard University’s Healthy Buildings program recommends four to six “clean air” exchanges per hour in classrooms, through any combination of ventilation and filtration.
“The current standard says three is acceptable, and in reality, the typical school only gets about half of that bare minimum,” the Lancet reports.
Phillips said HVAC systems in Memphis-Shelby County Schools are set to deliver five to eight air exchanges per hour. That calculation is based on what Phillips calls a classroom’s “breathing zone,” which is three to six feet above the floor.
An air quality expert at Harvard University says a more accurate calculation is closer to three air exchanges per hour.
“You measure air exchanges based on the entire volume of a room, floor to ceiling,” said Dr. Parham Azimi of Harvard’s T.H. Chan School of Public Health.
In February 2021, the CDC issued a new guidance. The agency emphasized the importance of social distancing and masking in classrooms but added nothing more about indoor air quality.
“Ventilation is given lip service with little guidance. Incredibly disappointing,” tweeted Richard Corsi, dean of engineering at Portland State University and an expert on indoor air quality. “The lack of understanding of ventilation or its importance (or perhaps just disregard) is wholly obvious.”
HVAC systems also use filters to remove allergens, infectious particles, and other contaminants from recirculated air.
Filters with higher MERV (minimum efficiency reporting value) ratings remove a greater percentage of particles.
ASHRAE recommends that schools use filters with MERV-13 or higher ratings. Many older HVAC systems can only accommodate MERV-8 or -9 filters.
Phillips said HVAC systems in all MSCS’s 184 buildings have MERV-9 filters or higher. Filters are replaced every four months.
“We’re going to have to replace the older systems before we can change all of them over to MERV-13,” Phillips said.
That process is in place, thanks to the federal government’s COVID relief funding.
Since the pandemic began, public schools in Shelby County have received more than $900 million in pandemic relief funds.
MSCS received $535 million, charter schools $131 million, and the Achievement School District $86 million. The six municipal school districts split nearly $100 million.
The MSCS board has approved spending about $120 million to replace aging systems in 29 schools. The district is planning to replace another 20 or so after that.
All local municipal school districts are using pandemic relief funds to upgrade or replace at least some of their HVAC units.
“We have upgraded nearly 100 units at various schools over the past several years, many of which were installed in the summer of 2020,” said Tim Ruff, director of operations for Arlington Community Schools. “Last year, once we returned from the March-May 2020 shutdowns, we began turning on the HVAC systems two hours prior to the start of school so it’s better ventilated by the time students and staff arrive.”
That’s a process called flushing, which gives HVAC systems time to ventilate and filter air before students arrive in classrooms.
Schools also can supplement less efficient filters by using portable air cleaners with HEPA (high efficiency particulate absorbing) filters.
“The science is pretty clear,” Harvard’s Health Building program reports. “Portables with a high-efficiency HEPA filter and sized for the appropriate room can capture 99.97% of airborne particles.”
In April 2021, ASHRAE and the Green Schools Council issued Preparation in the Pandemic, the first comprehensive study of indoor air quality strategies in schools “in response to the COVID-19 pandemic.”
ASHRAE and its 50,000 members set industry standards for HVAC systems
Preparation in the Pandemic listed “major IAQ strategies” endorsed by ASHRAE, the CDC, the EPA, the World Health Organization, the U.S. Green Schools Council, and American Institute of Architects, and Harvard’s Health Buildings Program.
- Better ventilation, which included opening windows, using fans, and setting HVAC systems to bring more fresh, outdoor air into school buildings. “That’s more difficult in hot and cold weather,” the report noted.
- Better filtration to remove airborne contaminants from recirculated indoor air. That included upgrading HVAC air filters to a MERV rating of 13 or higher and installing portable air cleaners that use HEPA filters. “These options can be much more expensive, but provide better protection from allergens than pathogens,” the report noted.
HEPA filters are used in hospitals, and clinical evidence shows that they can reduce viral infections. But most HVAC systems are not designed to push air through a HEPA filter’s tight weave.
While a national standard is clearly needed, at this stage, there is a long way to go to get there.
“The well-documented problems of poor indoor air quality in K-12 schools have been allowed to continue for decades,” the Bloomberg School of Public Health at Johns Hopkins University reported in May 2021. “A path forward is needed to fix these problems to give students, teachers, and staff in K-12 schools the healthy air they deserve.”
The Johns Hopkins report called on the Biden administration to convene a federal task force to “create standards for school systems to account for different ventilation systems, climates, and conditions around the country” as well as a “certification for HVAC installers and commissioners and … recommendations for oversight and accountability.”
That hasn’t happened.
Ben Wheeler, an intern for the Institute for Public Service Reporting, contributed to this story.
This story first appeared at dailymemphian.com under an exclusive use agreement with The Institute.