Better Indoor Air Quality in Schools: Infrastructure Solutions

OCTOBER 4, 2022 / BY ACTIVEPURE / 11 MINUTES OF READING

COVID-19 has made it apparent that our schools need indoor air quality improvements. School air quality is of particular importance because of how susceptible students are to airborne contaminants compared with adults, and how this susceptibility impacts their long-and-short-term academic, physical, mental, financial, and social well-being. In this 4-part series, we will explain the situation in our schools and what school districts can do about it.

In Part 1, we discussed how poor indoor air quality (IAQ) negatively impacts schools. In Part 2, we discussed how external and financial factors affect the air quality in schools while suggesting several solutions. In Part 3, we reviewed how school policy can negatively or positively affect air quality. This is Part 4: Infrastructure Solutions.

Building Infrastructure

No matter how well you set school policies, building infrastructure is the factor that most directly affects air quality. As PBS NewsHour put it, “[...]when it comes to a 94-year-old elementary school, ingenuity and dedication can only go so far.” We will discuss 3 components of building infrastructure: aging infrastructure, temperature/humidity/ventilation, and air cleaners.

Aging Infrastructure

Pictured: water and mold damage on a classroom ceiling. Damaged infrastructure can reduce indoor air quality. (Image Credit: Getty / Steve Dunning)

Considerations: If you are a school district leader, you have little control over the age of your school building. You also know that most schools have a problem with aging infrastructure. According to an article on the website of the National Educational Association, 50% of U.S. public schools are over 50 years old.¹ Or, as they put it more poetically in the same article's introduction, “Collapsing ceiling tiles, ice-cold water for handwashing, lead-lined water pipes, and unairconditioned rooms where temperatures can soar over 110 degrees—these are just some conditions educators report in their aging schools.”²

Aging infrastructure is a problem for several reasons. Leaking pipes and roofs can lead to mold growth. Flaking paint in buildings before 1978 can stir up lead dust,³ while crumbling ceilings, walls, and floors can send asbestos fibers into the air. (According to the advocacy group Asbestos.com, “If a school was built before the 1980s, it likely contains some form of asbestos.”)⁴ Similarly, polychlorinated biphenyls (PCBs) were once used in everything from paint to fluorescent lighting ballasts during the same timeframe.⁵ Per Diamond Pest Control, older buildings also tend to have more ways for allergen-shedding pests to infiltrate a building and more places for them to hide once they do. These same cracks and crevices help outdoor air pollution enter.

Solutions: The solution to aging infrastructure is the repair of damaged sections and the remediation of harmful substances. Repairs can be highly beneficial to school districts. For instance, improved test scores have been linked to mold remediation and roof repairs.⁶ Consider also that government funding is currently available for such repairs (as discussed in Part 2 of this series).

Lead, asbestos, and PCB remediation are more complicated; each would require an article unto itself. However, the first step is to avoid disturbing any substances suspected to contain lead, asbestos, or PCB. The second step is to test these suspected substances. You can buy DIY testing kits if you desire but be sure to follow all safety instructions. Different levels of intervention will be required based on the percentage of these substances present and where they are present. Considering the danger of such substances, it is best to discuss your school's situation one-on-one with a professional. However, your school district may find these flow charts developed by the University of Albany helpful. Please also see the EPA landing pages for asbestos in schools and PCB testing, as well as NYC's webpage on lead paint safety.

Temperature, Humidity, & Ventilation

An HVAC system running through a school cafeteria. A well-maintained HVAC system can be part—but not all—of an IAQ improvement plan. (Image Credit: Getty / Alexjey)

Considerations: Sealing buildings reduces the ability of pests and pollution to enter the building. However, the trend of airtight, energy-efficient buildings also creates separate air quality problems. A researcher at the University of New South Wales explains, “[...]since the energy crisis in the 1970s, building ventilation rates have decreased in order to conserve energy, which has tended to increase the residence time for indoor pollutants and decrease oxygen levels.”⁷ In other words, once contaminants get inside a well-sealed building, they have a hard time leaving. This is especially true of carbon dioxide, which as we mentioned in Part 1, often builds to levels that impair cognition and reduce performance. (As one paper put it, “reducing the CO₂ concentration from 2,300 ppm to 900 ppm would improve performance[…]by 5% and […]reducing CO₂ from 4,100 ppm to 1,000 ppm would increase daily attendance by 2.5%.”)⁸ Microbes can also take advantage of poor ventilation.⁹

However, schools can't simply open the window to clear the air. According to another team of researchers at the University of New South Wales, “Often, windows are closed to avoid discomfort caused by external noise from people, traffic and construction and extreme weather to prevent drafts.”¹⁰ In other words, if a classroom opens windows to increase ventilation, it is impairing the energy efficiency and thermal comfort of the entire building—not to mention letting pollutants, pests, and noise indoors.

As for schools that rely on HVAC rather than mechanical ventilation, they aren't faring much better. According to the National Education Association, “The most widespread problem [in schools] is outdated substandard ventilation. According to the American Society for Civil Engineers, 53 percent of public school districts report the need to update or replace multiple building systems, including HVAC systems.”¹¹ A recent Government Accountability Office report agrees that half of all U.S. schools need updates to their HVAC system.

Solutions: According to the ebook Unlocking Hidden Value in Class B/C Office Buildings, just keeping up with routine maintenance on your HVAC system can make an enormous difference in thermal comfort.¹² Per the California Air Resource Board, routine maintenance and inspection of your water heater and HVAC furnace are important for safety as well as a means of reducing air pollution.¹³

However, most school districts have more extensive ventilation problems. It might seem that the obvious solution to insufficient ventilation is simply to pump in more outside air through high-MERV filters. We respectfully disagree with this solution. Installing higher MERV filters into an existing HVAC system can strain the system, increasing energy and maintenance costs. Plus, all that additional outside air entering the building must be heated or cooled once more.

A better (yet imperfect) solution is demand control ventilation (DCV). DCV reduces or increases ventilation based on the occupancy level of the room. DCV also should circulate air between unoccupied and occupied areas of the building, thus saving heating and cooling costs while diluting CO₂. Fresh air can then be brought in at night when air pollution is at a low and the building's thermal comfort has a more flexible range.

However, DCV may not sufficiently reduce contaminants on its own. According to one study, “The DCV reduced the peak CO₂ concentration to 1335 ppm, while CO₂ raised to 2981 ppm in the classrooms without DCV during mid-season.”¹⁴ CO₂ above 1,000 is still unacceptable, so we need to layer on additional solutions.

Enthalpy recovery ventilators (ERV) can be of assistance here. These handy gadgets install into an HVAC system and transfer the moisture and temperature of outgoing indoor air to incoming outdoor air, thus preserving much of the heating or cooling your system has already performed. You can use an ERV by itself, or in conjunction with a DCV system.

Air-side economizers can be an alternative to DCV. Air-side economizers monitor the temperature outside and bring in outdoor air when doing so is most efficient for the heating and cooling system. However, they are not ideal for warm and humid climates.

You can use both an economizer and DCV system in conjunction, but according to the company New York Engineers, “While a DCV system will try to reduce the outdoor air supply in response to occupancy, the economizer will try to increase it to save on air conditioning. When DCV and an economizer are deployed together, the control system must be smart enough to detect which of the two savings is greater.”

Whatever you choose, it can do some good. According to a previously mentioned paper, “The average ventilation improvement project (~$300,000) improved math and reading scores by 0.07 [standard deviations (sds)] and 0.11 sds, respectively, and increased the probability of passing these tests by 2–3%.”¹⁵

Ventilation improvements are the only means of reducing excessive carbon dioxide. However, the COVID-19 pandemic has brought pathogens to the forefront of everyone's mind. Your district needs immediate solutions which deal directly with bacteria and viruses. That brings us to our final set of considerations and solutions.

Air Purifiers

The Pure & Clean with ActivePure Technology in action.

Considerations: One of the most common types of air cleaners is the fibrous air filter. Whether installed in the ducts of your HVAC system or as a portable device, these purifiers work by capturing small particles such as dust, pollen, bacteria, and mold spores. However, the more effective the filter, the more energy it takes to push air through that filter.

Ultraviolet purifiers are also gaining traction lately among schools. They can be installed as fixtures in the HVAC system or ceiling, and also appear as portable purifiers. The goal of such a system is to neutralize bacteria, viruses, and mold spores through exposure to UV light. However, portable UV purifiers have dubious success rates, and upper room UV is less-effective than might be desired at handling certain pathogens.

The main problem with both these types of popular purifiers, however, is that they are passive—that is, contaminants must pass through their internal mechanism (possibly on the other side of the room) in order to be eliminated.

Solutions: The solution to passive purifiers is active purifiers. Rather than relying on ventilation to dilute pathogens or filters to trap pathogens, active purifiers react with contaminants out in the room itself. For instance, devices with ActivePure Technology produce oxygenated molecules which meet mold, bacteria, and viruses out in the room—neutralizing them on surfaces and in the air 24/7.¹⁶

Devices with ActivePure Technology have been proven to reduce 99.99% of many common types of bacteria, viruses, and mold spores, including the virus which causes COVID-19. For instance, the Aerus Pure & Clean with ActivePure Technology was proven to reduce airborne SARS-CoV-2 below the detection limit in one minute.

ActivePure Technology can be found in flexible formats based on your school's needs. Our induct purifiers are out-of-the-way plugins that work with your existing HVAC system. If your school does not have an HVAC system, our portable purifiers plug directly into the wall and start working in seconds. ActivePure devices can also be installed on buses.

ActivePure can also help with energy efficiency. For instance, most devices use only as much power as a lightbulb. Plus, our devices don’t require straining your HVAC system with high-MERV filters.

One reason we can save your school district energy costs is that our induct purifiers do not require installing high-MERV filters into the HVAC system (which can increase energy costs). One customer of ours—a Fortune 500 company—saw a 96% decrease in surface bacteria counts using ActivePure devices paired with MERV-8 filters compared to when they were using UV technology paired with MERV-13.¹⁷