Clean air in schools is an important part of creating a healthy learning environment, especially for children’s developing lungs. Unfortunately, the Environmental Protection Agency (EPA) estimates that up to half of all schools have problems linked to indoor air quality. Poor air quality can cause asthma flare-ups, unwanted absences, and even make it harder for students to concentrate and do well on tests. One of the major factors that can put individuals at risk is radon – a dangerous gas that causes lung cancer. Since you can’t see, smell or taste radon, many times school administrators don’t even know that their school has a dangerous level of radon.
Why Radon Matters in Schools
Radon forms naturally when uranium in soil and rock breaks down. Because radon is a gas, it easily seeps through any cracks in walls, basements, floors and foundations. The EPA has found that nearly one in five schools in the U.S. has at least one schoolroom with high levels of radon.
When we breathe air with radon, tiny radioactive particles get trapped in our lungs. These particles release low-level radiation that damages lung cells and, over time, can lead to lung cancer. In fact, radon is the second-leading cause of lung cancer in the U.S., causing about 21,000 deaths a year. Though radon doesn’t make someone sick right away, breathing it in over time, like a child who spends many hours a week in the classroom, can lead to serious health problems. In addition, children are particularly vulnerable because they breathe more air relative to their size and their lungs are still developing. This means they might absorb more radon into their lungs than adults, even if radon levels are the same.
Testing to Protect Students
The only way to know if a school has unsafe radon levels is to test for it. Darrell Thompson Jr., director of facilities at Center Grove Community School Corporation described simply why radon testing is so important, “we want to maintain the best indoor air quality possible to help keep our students and staff healthy.” Recently, his schools were tested for radon, and he was amazed by how simple and non-disruptive the process was.
He began by hiring a certified radon professional, who outlined the process and proposed dates to complete the testing. School radon testing guidance includes placing test kits for 2-7 days in every room that touches the ground and at least 10% of rooms that don't. That includes all classrooms, offices, gyms, cafeterias and arts rooms on the ground level. For best results, testing should take place during the cooler months of the year when buildings are closed and HVAC systems are running normally. The testing also needs to be done during regular school hours when the building is occupied, not during weekends or holidays. “It was much easier than I had anticipated and not nearly as expensive as I had expected. It was very much worth the minimal effort,” Darrell continued.
Fixing a Radon Problem
Once all rounds of testing are completed, if results show radon levels are above 4.0 picocuries per liter (pCi/L), the school should take action to fix the problem. The American Lung Association and the EPA also recommend considering mitigation if radon levels are between 2.0 and 4.0 pCi/L.
To fix a radon problem in a school building, a radon mitigation system should be installed by a radon mitigation specialist. This typically consists of a vent pipe and fan that work continuously to collect radon gas from beneath the school's foundation and vent it outdoors. The specialist will also seal cracks in the baseline floor and foundation to ensure the mitigation system is as effective as possible.
After mitigation, schools should test again within 30 days to make sure the system is working properly, then every two years after that. Schools with radon levels under 4.0 pCi/L should be retested every five years or if there are any significant changes to the school, such as a new HVAC system or foundation.
Educating Staff and Parents
Before radon testing occurs, it can be helpful to notify staff and parents. "The only concern we had was how the testing may disrupt the learning day,” Darrell explained. “It turned out to be no issue at all because the contractor was very aware of his environment and all staff were given prior notice well in advance, so they were not surprised by something they were not expecting.” Being transparent with staff and parents also allows them to learn more about the dangers of radon and steps they can take in and outside of the school to keep their indoor air environment safe.
Healthy indoor air quality helps students think better, miss fewer school days, and stay free from disease. Radon may be invisible, but its effects are real — and testing, fixing, and mitigating are all needed to keep students and staff safe long-term.
To learn more about how to keep your schools indoor air safe, visit our Radon in Schools page or join the Clean Air in School challenge.
Blog last updated: January 27, 2026
