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NEA Toolkit

Addressing Indoor Air Quality in Schools

The Importance of Indoor Air Quality in Schools for Improved Educational Outcomes and Occupant Health
High School girl looking through microscope
Published: January 4, 2023
This resource originally appeared on

Nearly 57.5 million students and school employees enter the doors of our nation’s schools every day. According to estimates from the U.S. Environmental Protection Agency, half of these adults and children spend their school days breathing air polluted with toxic chemicals, mold, viruses, bacteria, asbestos, pesticides, smog and particulates from vehicle pollution, and more. Despite efforts by school employees and their unions to improve indoor environmental quality in classrooms and other school buildings, many of the conditions that cause unhealthy indoor air and environmental quality continue to plague our nation’s schools.

Poor indoor air and environmental quality results from:

  • Deferred building maintenance, which leads to dampness, mold, high humidity and uncontrolled classroom temperatures;
  • Improper ventilation, which is the result of outdated designs, aging or badly maintained systems, or human error;
  • Site contamination from toxic chemicals previously used or dumped at the school site, no environmental testing of sites, or poor leasing practices;
  • Hazardous neighbors; school locations are located close to known sources of air pollution and contaminated facilities;
  • Toxic construction materials, which are often banned or no longer used, but still in place in many schools;
  • Unhealthy practices, such as misuse of harsh cleaning products that can cause asthma and lung irritation; and
  • An absence of state or federal mandatory standards that would ensure healthy indoor air in all schools.

The underlying conditions in schools that cause poor indoor air and environmental quality harm not only the health of students and school employees, they also limit academic achievement and teacher and staff productivity. Whether inadequate ventilation, deferred maintenance or toxic chemicals are making the air unhealthy in any particular school, these conditions result in a variety of common problems that the educational system must grapple with every day.

Poor indoor air and environmental quality:

  • Increases the severity and frequency of asthma, allergies and other respiratory illnesses;
  • Aids transmission of viruses and bacteria resulting in more colds, flu and serious infectious diseases, such as pertussis or tuberculosis;
  • Can raise the risk of long-term, even life-threatening illnesses, such as cancer and cardiovascular disease, particularly among school employees;
  • Leads to more school and workdays missed;
  • Results in higher medical bills and more doctor visits for all
  • Lowers student scores on standardized math and reading tests;
  • Leads to higher dropout rates, limiting students’ long-term potential and earning power; and
  • Increases school employee dissatisfaction and staff turnover.

Indoor air and environmental quality solutions must incorporate racial and social justice analyses so that marginalized communities are not further disadvantaged by the failure to identify and remediate these problems their schools face or to dedicate the resources necessary to do so.

The EPA's Science Advisory Board has consistently ranked indoor air pollution among the top five environmental risks to public health.

It is estimated that Americans spend about 90 percent of their time indoors where levels of pollutants may be two to five times higher than outdoor levels, reaching more than 100 times higher on occasion. Comparative risk studies by the EPA’s Science Advisory Board place indoor air pollution among the top five environmental risks to public health.

Ventilation rates in classrooms regularly fall below minimum standards necessary for a healthy indoor environment, and HVAC (heating, ventilating and air-conditioning) systems in many U.S. schools are failing.

A 2017 literature review found that school ventilation rates regularly fall below the ASHRAE (formerly, the American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards deemed necessary for a healthy indoor environment. Proper installation, operation and maintenance of HVAC systems are key to proper ventilation in classrooms, but existing systems often fall short. In addition, many schools do not have HVAC systems. A study by the University of California, Davis, and Lawrence Berkeley National Laboratory, for example, found that nearly 85 percent of newly installed HVAC systems in California schools failed to provide sufficient ventilation. A 2020 analysis of U.S. schools by the United States Governmental Accountability Office found that 41 percent of school districts need to update or replace HVAC systems in at least half of their schools.

Good indoor air quality contributes to healthier indoor environments and better student outcomes.

The 2017 literature review found a positive association between ventilation rates and student health and performance. For example, higher ventilation rates were associated with a decrease in absences and reductions in visits to the school nurse for respiratory symptoms. Asthma, mold and other problems also can be mitigated by appropriate ventilation. A study of 100 U.S. schools found a direct association between student academic achievement and classroom ventilation rates, and that measurable progress in math and reading scores were observed when school indoor air quality was improved. Finally, as the EPA writes: “Good indoor air quality is shown to promote a pleasing learning and working environment, along with promoting a sense of welfare. A positive working and learning environment assist schools in providing the most efficient education for students.” 

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Keeping the Promise of Public Education

ESEA is the largest ESP local in the United States and is a full-service employee association which is an affiliate of the Nevada State Education Association (NSEA) and the National Education Association (NEA), the largest national association representing education employees in the United States.