Think of it this way: In the 1800s when London tamped down a cholera outbreak, a bacterial disease usually spread in water, it did so by upgrading its sewer system. In a similar manner, some of the world’s top building scientists are now arguing that ventilation and filtration system upgrades are necessary to cut down on airborne diseases like COVID-19. In an editorial published last year in the academic journal Science, these experts called for a radical shift in our thinking: “Building ventilation systems must get much better,” they wrote.
A report by FutureEd found that nationally, more than half of the thousands of school districts surveyed are using federal COVID aid to upgrade ventilation systems, something that’s being encouraged by the U.S. Department of Education. Evidence from New York City and Quebec indicates that schools with better ventilation or filtration have fewer COVID-19 cases.
Waibel Energy Systems in Vandalia has worked with nearly 50 clients, not just schools, during the pandemic to assess and improve indoor air quality. Bryan Schenk, the healthy building leader at Waibel Energy Systems, pointed out that the U.S. Environmental Protection Agency ranks indoor air quality as one of the top five most urgent environmental risks to public health, and not just because of COVID-19.
Schenk said the pandemic has simply brought attention to indoor air quality from outside the building industry. On top of fostering occupants’ health, increasing a building’s clean air can boost productivity and focus.
“In schools, that means improved performance on tests and other screenings for students, as well as increased attendance,” Schenk said. “For teachers, that means improved performance and the ability for students to stay engaged with lessons for longer periods. In an office setting, that means improved productivity throughout the work day.”
Studies have found a correlation between better ventilation and higher student test scores.
People (salaries, health benefits, etc.) are hundreds of times more expensive than energy costs or using better filters, said Wade Conlan, an engineer at Hanson who leads the building readiness team at the American Society of Heating, Refrigerating and Air-Conditioning Engineers.
Upgrades that school districts and other building owners could make to improve indoor air quality range from immediate solutions that cost a few thousand dollars (like assessing their systems or installing better filters) to expensive overhauls of HVAC systems.
“Maintaining our facilities and providing safe and effective learning environments for our students and staff continues to be a priority for the district,” said Jon Wesney, the Centerville City Schools director of business operations.
Local schools make improvements
Dayton Public, Huber Heights and Centerville, three of the largest school districts in Montgomery County, have plans or have already used federal COVID-19 funds to upgrade their HVAC systems. Northmont schools also upgraded HVAC using COVID-19 money.
Centerville schools spent about $3.7 million between federal COVID-19 dollars and its own money to upgrade its HVAC systems in the buildings between 2020 and 2021, said Sarah Swan, the district’s spokeswoman. Centerville schools got more than $9 million in federal COVID-19 relief, according to the Ohio Department of Education.
“During the past school year, we focused on maximizing air flow by increasing the amount of fresh outdoor air circulating within our buildings,” Wesney said. “This included controlling and monitoring the amount of fresh air by adjusting HVAC programming controls to increase ventilation, as well as installing MERV-13 filters, as recommended by the CDC.”
Other school districts are still working on plans to upgrade their building’s HVAC. Dayton Public Schools expects to present a plan to the Dayton Public School Board sometime in the spring to use $13.5 million of its federal COVID-19 relief dollars on upgrading HVAC systems, said Elizabeth Lolli, the superintendent, including replacing outdated systems. Dayton Public got more than $141 million in COVID-19 relief aid.
Northmont schools spent $280,031 in relief funds to upgrade HVAC at six of the district’s buildings. The last two buildings were newer, said district spokeswoman Jenny Wood. The district got about $8.3 million overall in COVID-19 relief money, according to ODE.
Wood noted some of the district’s buildings are more than 50 years old.
“The equipment was installed to not only just help purify the air in our buildings to help against COVID-19, but also for the residual benefits of increased air quality during the normal cold and flu season,” Wood said.
Huber Heights also plans to use some of its federal money on HVAC and building upgrades, but does not have a specific amount budgeted yet.
Not all schools plan to upgrade. Kristy Creel, a spokeswoman for Xenia schools, cited the district’s newer systems, built in 2012, and its plan to open a new middle school in 2024. The district does not plan to spend federal COVID-19 funds on updating HVAC. Instead, the district spent the money on remote teachers, technology and cleaning supplies, she said.
Fairborn spokeswoman Pam Gayheart said that district does not plan to use COVID-19 dollars for HVAC upgrades. Fairborn voters passed a levy in 2020 to build a high school and middle school. The district is currently building an intermediate school, set to open in the fall, and opened a primary school in 2020.
What building experts recommend
A century ago, it was standard practice to circulate more outdoor air in buildings to fight airborne infections, said William Bahnfleth, an architectural engineering professor at Pennsylvania State University, chair of the ASHRAE Epidemic Task Force and a signatory on the Science editorial.
“At some point, we assumed that medicine could pretty much take care of infectious diseases. You could be vaccinated against some of the worst things,” Bahnfleth said. “After the pandemic, we need to rethink and do something about addressing infection and risk mitigation with new quality standards.”
Many early preventative measures for COVID-19 focused on surface cleaning, before it became widely accepted that the disease spreads through the air, he said.
Recommendations on how buildings can reduce airborne infectious aerosols from ASHRAE include:
- Assess current HVAC systems to make sure they are operating as intended and meeting minimum standards for outdoor airflow.
- Increase outdoor air coming into the building through ventilation.
- Filter indoor air. This can be achieved by using filters rated at MERV-13 or better in central HVAC systems or freestanding air cleaners in rooms.
- Only use air cleaners for which the evidence of effectiveness and safety is clear. Steer clear of unproven methods like ionizer air purifiers and devices that use hydrogen peroxide photocatalytic oxidation. Research into these emerging technologies show mixed results.
Conlan said assessing a building’s HVAC system should be the first step and may cost a few thousand dollars for a midsized building. Too often, for example, building operators close sources of outdoor air to save on heating and cooling costs and aren’t meeting minimum standards for outdoor airflow, he said.
Then it is a matter of considering whether to increase outdoor airflow or use other engineering controls. It’s a balancing act since increasing outdoor air coming into the building can increase heating and cooling costs. But the future of HVAC systems may be building customizable systems that can bring in more outdoor air during surges of COVID, flu or other airborne illness, but cut down on this when the risk is lower, posited Bahnfleth.
Conlan said spending a bit more on air filters is the next best step. Buildings already have to replace filters in central units every few months and likely are already using MERV-8 filters. So upgrading to better filters (MERV-13 is recommended) would reduce particles and airborne contaminants and only cost about 20% to 30% more, Conlan estimated.
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