Indoor Air Quality in Schools Guide
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Helping schools with the resources they need to improve the quality and health of their indoor air.

As the nation continues to battle the COVID pandemic, institutions across the country, including schools, are working hard to ensure a safe reopening. According to the guidance issued by the Centers for Disease Control and Prevention (CDC), ensuring safe operations in schools requires maintaining healthy facilities – this includes adequate ventilation for good indoor air quality.1

A 2020 study from the U.S. Government Accountability Office shows 41 percent of schools need to update or replace their ventilation systems.2

The Basics

How does indoor air quality impact learning?

Research has shown indoor air quality can be quite detrimental to student performance and attendance.

Improving IAQ has been shown to:

  • Improve student performance including addition skills, number comparison, and reading and comprehension4,5
  • Reduce absenteeism due to lung diseases such as asthma.6 Asthma is one of the leading causes of school absenteeism causing an estimated 13.8 million lost school days in children ages 5-17.6 Children with asthma are especially vulnerable to environmental asthma triggers found indoors in many school buildings.7 Take the Lung Association’s Asthma Basics online module to learn more.
  • Reduce radon exposure, which is responsible for 21,000 lung cancer deaths in the US each year. Take the Lung Association’s Radon Basics online module to learn more.

What is Indoor Air Quality (IAQ)?

The air you breathe is filled with lots of things including gases and particles—most are too small to see with the naked eye and may cause harm to your body when ingested. That is why ensuring your indoor air is free of harmful gases and particles is important. This is called indoor air quality.

Schools should ideally serve as optimal learning environments for students, but poor air quality in a school’s building can actually have negative effects. It is estimated that pollutants are up to five times higher indoors than outdoors. This is important as children (and adults) spend up to 90% of their time indoors.3

What causes poor indoor air quality in schools?

There are several variables that can cause poor indoor air quality:

  • Indoor/Outdoor air pollutants (including mold, chemicals, fumes, etc.)
  • Poor air filtration
  • Poor air flow
  • Improper room pressurization/ventilation
  • Temperature (either too hot or too cold)
  • High or low humidity

Air pollutants can be gases or particles—carbon dioxide and carbon monoxide are the most common gas contaminants. Carbon monoxide may come from improperly vented furnaces or exhausted fumes returning into the building. Carbon dioxide, while not deadly, mostly comes from exhaled air from students and teachers in the classroom and can be compounded with poor ventilation.

See the full guide for more information on air pollutants.

What You Can Do

How can I assess/monitor IAQ in my school?

Five indoor air quality measurements are important for schools.

  1. Temperature
  2. Relative humidity
  3. Air movement
  4. Airflow volume
  5. Carbon dioxide (CO2) monitor is useful for indicating when outdoor air ventilation may be inadequate.

These five measures are readily available, do not require expensive equipment or special training, and are straightforward to interpret. There are various devices that measure indoor air quality. If your school’s budget does not allow the purchase of some, or all, of the equipment, you can borrow equipment from an EPA Regional Office. Find your EPA Regional Offices.

If you cannot obtain the recommended equipment due to lack of resources, prioritize your equipment purchases as follows:8

  1. Temperature, relative humidity and chemical smoke device for indicating air movement.
  2.  Airflow volume measuring devices and CO2 monitor.

What are simple, low-cost solutions to improve IAQ in my school?

The healthiest and most sustainable approach to improving indoor air quality in your school is to:

  1. Assess the indoor air quality to establish a baseline and understand where improvements are needed
  2. Improve ventilation to increase circulation of fresh air
  3. Improve filtration of circulating air

There are low-cost, low-tech options to improve ventilation and filtration, including:

  • Opening windows and doors when weather and safety conditions allow to increase outdoor air flow.
  • Using fans to exhaust room air to the outdoors and to get a cross-wind.
  • Using wireless, battery-operated indoor air quality devices that can monitor a wide array of air quality issues (e.g. temperature, humidity, CO2, radon).
  • Educate! Students today care so much about their health and the planet around them. Educating about air quality both indoors and outdoors will help everyone be safer and more productive.

See the full guide for more information on low-cost options to improve IAQ.

How do I select the right products to improve IAQ in my school?

There are a lot of gimmicks marketed to improve air quality. The Lung Association is concerned about products that add chemicals to the air—foggers, electrostatic sprayers, spraying disinfectants and air fresheners. Many of these products end up polluting the indoor air further.

An indoor air quality monitor may a good first step to getting an overview of the IAQ is in your school. When selecting an IAQ monitoring system for your school, there are some key things to consider:

  • Does the system monitor the most important contaminants? (CO2, temperature, humidity)?
  • Is the system easy to install and use for facility managers and teachers?
  • Can the system provide reports over time to document IAQ levels?
  • Is the system scalable? (i.e., can a school start with 1-2 spaces and expand to additional rooms as budget/need becomes available?)

Funds & Services

What are big picture ways to address IAQ in my school?

According to the Centers for Disease Control and Prevention (CDC), the essential elements for safe and healthy schools include adequate ventilation for good indoor air quality.9

Between the relief bill passed in December 2020 and the American Rescue Plan passed on March 11, 2021, the Federal government has approved $176 billion in emergency COVID-19 relief aid for K-12 schools. Facility-related expenditures are among the allowable uses for these funds and are an excellent opportunity to invest in the indoor air quality of children and schools with no out-of-pocket expense.

Learn more about indoor air quality at school

What is the CARES Act?

The Coronavirus Aid, Relief, and Economic Security Act (CARES Act) authorized two programs that provide equitable services:

  • Elementary and Secondary School Emergency Relief Fund (ESSER)
    State Educational Agencies (SEAs) must allocate the ESSER funds to school districts. There are 12 uses of these funds, including repairing school facilities, especially ventilation systems, to improve air quality and reduce spread of the coronavirus.
  • Governor’s Emergency Education Relief Fund (GEER)
    Flexible block grants that each Governor will allocate. There are also 12 uses of these funds, including providing principals and other school leaders with the resources necessary to address the needs of their individual schools.

How can my school access CARES Act funding?

School districts must apply to State Education Agencies to access ESSER funds. Check with your State Department of Education about the application process and deadlines.  Below is a list of specific points you should be prepared to address in your application.

  1. Explain the purpose of the project or equipment.
  2. Explain how the completed construction, remodeling, or equipment is necessary and a direct result of the COVID-19 public health emergency.
  3. Describe where the remodeling or construction is to occur.
  4. State whether the area is owned by the local educational agency (LEA) or if it is leased space.
  5. Provide an estimate of the total cost of the project.

Download the full guide for a complete list of points for the CARES Act application

There are many reputable indoor air quality and HVAC companies that offer free analysis of schools to evaluate current systems and identify proposed changes/upgrades to assist schools with improving indoor air quality.

Promotional support for the Indoor Air Quality in Schools Guide generously provided by Airthings and Carrier Colorado.


  1. Operational Strategy for K-12 Schools through Phased Prevention. Centers for Disease Control and Prevention. Updated May 15, 2021. Accessed at
  2. K-12 Education: School Districts Frequently Identified Multiple Building Systems Needing Updates or Replacement. US Government Accountability Office. June 2020. Accessed at
  4. Fisk, WJ. The ventilation problem in schools: literature review. Indoor Air. 2017; 27: 1039– 1051.
  5. S, Jensen KL, Pedersen AL, Rasmussen HS. The effect of increased classroom ventilation rate indicated by reduced CO2 concentration on the performance of schoolwork by children. Indoor Air. 2016 Jun;26(3):366-79. doi: 10.1111/ina.12210. Epub 2015 Apr 27. PMID: 25866236.)
  6. Centers for Disease Control and Prevention.  National Center for Health Statistics.  National Health Interview Survey, 2015.  Analysis by the American Lung Association Epidemiology and Statistics Unity using SPSS software.
  7. Moonie PhD, Sheniz, et al.  The Relationship between school absence, academic performance, and asthma status.   Journal of School health (2008).   Vol. 78, No. 3.
  9. Operational Strategy for K-12 Schools through Phased Prevention.  Centers for Disease Control and Prevention.  Updated May 15, 2021.  Accessed at
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