The health and performance of students and staff can be affected by a myriad of factors found in school built environments. As school districts across the U.S. are increasingly challenged by climate disasters, implementing strategies to maintain safe and healthy learning spaces is critical for continued operations. This overview highlights some of the key environmental factors to prepare schools for climate resilience and outlines science-informed strategies for protecting student and staff health.

Indoor air quality

As wildfires become increasingly severe and prevalent, it is crucial to defend against their impact on indoor air quality (IAQ) to keep schools operating safely during smoke events. Additionally, rising temperatures have been associated with increased pollen concentration, and more frequent storm events can increase risk for mold growth. Infiltration of outdoor air pollution, such as particulate matter from wildfire smoke, allergens and mold, as well as indoor-generated pollutants such as carbon dioxide (CO2), all pose health risks that require prevention or mitigation.

When carbon dioxide levels exceed the recommended maximum in classrooms, they can cause attention issues in students.

To mitigate these risks, schools can take the following steps.

Monitor outdoor and indoor air quality: Outdoor air pollutants can easily infiltrate building envelopes through open or leaking windows and doors, which is why it is important to stay informed about local outdoor air quality through real-time monitoring resources such as AirNow or BreezoMeter. If the outdoor air quality is poor—for example, if the air quality index is greater than 100—keep all classroom windows closed, close the fresh-air intake of heating, ventilation and air-conditioning (HVAC) units, and turn on portable HEPA air cleaners. Additionally, IAQ monitors can help schools apply a data-driven approach to indoor environmental quality (IEQ) monitoring by tracking particulate-matter pollution, temperature, humidity, carbon dioxide and other air quality parameters.
Enhance ventilation: Ventilation systems can play an important role in diluting pollutant concentrations that have built up indoors by bringing in fresh outdoor air. One study found that doubling the outdoor air supply rate to classrooms improved the speed of schoolwork performance by about 8%. Improved ventilation can include strategies such as HVAC upgrades, routine maintenance or adjusting systems to increase outdoor air intake.
Improve filtration: Adding portable HEPA air purifiers, upgrading HVAC system filters with a minimum efficiency reporting value rating of at least 13 and ensuring regular filter maintenance can help reduce the concentration of indoor air pollutants. One study found that using four portable HEPA air purifiers in a school classroom reduced the concentration of aerosols by over 90% within a 30-minute period (with an air exchange rate of 5.5 h⁻¹) compared with a neighboring classroom without air purifiers.

Images show where four IAQ monitors were installed in a classroom

IAQ monitors were installed in Kansas schools as part of the Delos–Kansas Department of Public Health air-quality-monitoring program. Photo courtesy of Delos Living.

Water access and quality

In the event of a natural disaster or power outage, ensuring access to safe drinking water is critical for immediately responding to emergencies, maintaining operations and supporting school communities. Promoting students’ overall water consumption may also improve learning outcomes, as even mild to moderate dehydration can lead to impaired performance in tasks that require attention and psychomotor and memory skills. Additionally, ensuring that drinking water is free of harmful pollutants such as lead is critical, as such pollutants have been linked to behavior and learning problems, lower IQ, hyperactivity, slowed growth and anemia in children.

Schools can take the following steps to ensure safe drinking water.

Conduct regular water quality testing: Twenty-four U.S. states and the District of Columbia had lead-testing programs for school drinking water as of 2018.
Conduct regular maintenance: Ensure that faucet and water fountain aerators and components are well-maintained and cleaned regularly to reduce possible bacterial contamination and make drinking water stations more appealing to students.
Prepare for extended closures: Following prolonged closures due to climate hazards or school breaks, conduct appropriate flushing procedures of drinking water sources. Maintain water heaters to reduce the risk of Legionella growth by keeping water temperatures below below 77 degrees Fahrenheit or above 113 degrees.

Thermal environment

Children are more vulnerable to the effects of extreme temperatures and ambient humidity levels. Both temperature and humidity greatly influence our thermal comfort, and studies have consistently shown that children perform better in cooler environments. In fact, a study of 75,000 high school students in New York City, New York, found that students were more likely to fail an exam on a 90-degree day than a 75-degree day.

To improve the thermal environment for students and staff, schools can take the following steps.

Invest in reliable heating and cooling systems: Proper heating and cooling systems in schools are essential to creating a thermally comfortable environment and can also lead to health improvements.
Purchase humidifiers or dehumidifiers: The Environmental Protection Agency recommends maintaining indoor relative humidity levels at between 30% and 60% in school buildings. Schools should consider installing whole-building dehumidification or humidification in their HVAC systems, or use portable dehumidifiers or humidifiers (humidifier use is especially beneficial during the cold season).

Materials

As our climate changes and extreme weather events become more frequent, it's crucial to choose building materials that are resilient to heat, safeguarding the building envelope against excessive heat gain and preventing the infiltration of polluted air and water. Studies have shown that elevated indoor temperatures resulting from extreme heat events can be associated with increased chemical emissions rates from building materials. Hazardous materials such as lead, asbestos and volatile organic compounds (VOCs) can be found in building materials, furniture and even cleaning supplies. These toxins and chemicals may have detrimental effects on health, ranging from skin irritation to neurological issues, learning disabilities, endocrine disruption and, in extreme cases, cancer.

Schools can take the steps that follow to ensure that safe materials are used within school environments.

Purchase IEQ-safe products: Effective, safer and nontoxic substitutes are often available for cleaning products, furniture and building materials. Product certifications, such as Green Seal and Greenguard Gold, are helpful for identifying materials that are conducive to good IEQ.
Install air purifiers: Consider installing air purifiers with adsorbent media filters such as activated carbon or chemisorbant media filters that are designed to help reduce harmful gaseous pollutants such as VOCs.

How climate-resilient schools can enhance student health and learning