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5 Key Indoor Air Quality Issues in Schools

October 3, 2022 jill Blog


By Regina Vaicekonyte

In response to the Covid-19 pandemic, many schools across the nation are now prioritizing IAQ and ventilation. The Center for Green Schools recently published a report detailing indoor air quality measures schools have implemented in response to the pandemic.

The study found that among the 47 school districts and independent schools surveyed, 87% increased outdoor air supply through existing HVAC systems, 77% imposed a pre/post-occupancy flushing strategy and 70% upgraded their filters in at least some of their schools.

Here are the five common IAQ issues in schools:

  1. Infiltration of Ambient Air Pollution

IAQ is significantly influenced by outdoor air quality, due to the infiltration of air from the outside. Once inside, pollutants can accumulate, and research shows that the concentration of toxins, allergens and other pollutants can be up to five times higher indoors than it is outside. Outdoor air pollution can negatively influence students’ attendance and performance.

For example, one study of public schools in Michigan found that schools located in areas with the highest air pollution levels had the lowest attendance rates and the highest proportion of students failing to meet state educational testing standards.

  1. Allergens & Asthma Triggers

Indoor environmental exposures to substances such as pollen, dust mites and pests – which are commonly present in schools – can cause allergic reactions in many people. Common symptoms of allergic reactions are similar to those of a cold, including a runny nose and congestion, sneezing, and watery eyes. Asthma often accompanies allergies, and asthma symptoms in the lungs and airways can be triggered by the same allergens.

Seasonal pollen allergies are linked to poorer cognitive performance, which can affect educational outcomes. In fact, researchers have found that students score worse on tests when pollen counts are high or when they are experiencing allergy symptoms.

  1. Dampness and Mold

Building dampness and mold in schools have been associated with increased respiratory health symptoms such as coughing, wheezing and allergic rhinitis; greater prevalence of asthma; and respiratory-related absenteeism.

A study of over 1,000 school children found that the concentration of mold found in floor dust was associated with headache, dizziness, and concentration problems. In the U.S., allergic rhinitis causes about two million – and asthma about seven million – lost school days per year among children and adolescents. In fact, asthma is the leading cause of school absenteeism in the U.S. due to chronic illness.

  1. High Levels of Carbon Dioxide (CO2)

CO2 levels are a good indicator of how much fresh air there is in an indoor space; the higher the levels of CO2, the less fresh air there is. Without fresh air, it is harder for indoor pollutants to disperse, and their levels can build up.

CO2 can also have a direct negative impact on cognitive performance; elevated levels of CO2 have been associated with increased student absence and symptoms of sick building syndrome, as well as wheezing among children attending daycare. In classrooms, higher CO2 levels have also been linked to poorer concentration and cognitive performance, among other indicators of poor academic performance.

A study conducted among students aged 10-11 found that increased levels of CO2 (from a mean of 690 ppm to a mean of 2,909 ppm) led to a decrease in “power of attention” of approximately 5%, which is similar to the impact a student might feel from skipping breakfast.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends that indoor CO2 concentrations be maintained below 1,000 parts per million. However, studies of CO2 levels in classrooms find that they often exceed recommended maximums.

A 2017 review found that the average and median peak values of CO2 in schools across the world, in the time periods studied, were always over 1,000 ppm, and often over 2,000 ppm, while maximum peak values ranged from about 3,000 to 6,000 ppm.

  1. Radon

Radon is a colorless, odorless, radioactive gas that is released from the breakdown of radioactive elements in rocks and soil, and can seep into buildings from cracks in floors, construction joints, and/or around service pipes.

According to EPA estimates, radon is the number one cause of lung cancer among non-smokers, and is the second leading cause of lung cancer in the U.S. (after smoking), leading to 21,000 deaths a year.

Studies have shown that the risk of lung cancer due to exposure to radon in children may be up to three times higher compared to adults, due to differences in lung shape and size. The EPA estimates that 70,000+ schoolrooms in use today have high short-term radon levels.

Improving IAQ not only helps to protect students and staff from airborne diseases, such as Covid-19 and the flu, but can also improve student productivity and performance. Cleaner air in schools can help to create learning environments where students and teachers alike can thrive.

Regina Vaicekonyte, MSc, WELL AP, is a vice president at Delos Labs, Built on a ground-breaking collaboration between experts across the health sciences and building sciences, Delos helps transform indoor environments into vehicles for health, well-being, performance and resilience.


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