Skip to main content
Add as a preferred source on Google

Classroom Purifier Cuts Infection Risks in Half—Same as Opening Windows

  • By Dian Schaffhauser
  • 03/08/21

A study in two South Korean high schools found that window ventilation reduced the risk of COVID-19 infection by 55%, while the use of an air purifier shrank the risk by 50%. The combination of the two dropped the risk by nearly three-quarters (73%). Researchers from the Infrastructure Safety department at the Korea Institute of Civil Engineering and Building Technology (KICT) said the use of the air-purifying device worked best when it was placed in the middle of the room, which was sized to hold about 25 students.

The study ran several rounds in which the performance of various antiviral and antibacterial air purifiers was tested in an actual classroom. Virus-like salt microparticles were released into the air as aerosols, and the researchers measured the concentration levels in succession in the center and at the edge of the room during each round to simulate the presence of an infectious student.

For a final round, the researchers worked with a specific air purifier: the AiroDoctor WAD-M20. The testing, which ran over the course of several days, assumed that students didn't move about the space and maintained distances from each other.

The AiroDoctor is a $4,000, free-standing device about the size of a 13-gallon garbage can. According to coverage of the study, students weren't bothered by noise from the machine.

"We are very pleased about the groundbreaking results from South Korea," said Carsten Hermann, managing director of ScreenSource GmbH, which produces the machine, in a press release. "We trust that the relevant authorities nationally and internationally will take notice of such important studies. After all, the globally unique filter technology of the AiroDoctor can make an important contribution in a long-term strategy against SARS-CoV-2."

About the Author

Dian Schaffhauser is a former senior contributing editor for 1105 Media's education publications THE Journal, Campus Technology and Spaces4Learning.

Featured

  • Dallas ISD Voters Approve $6.2B Bond Package

    Dallas ISD voters have approved a record-setting $6.2-billion bond package that district leaders say will modernize aging campuses, eliminate portable classrooms and reshape learning environments across one of the nation’s largest school systems.

  • Can AI Help Build Stronger Communities in Student Housing?

    Student housing success is shifting from operational performance to student experience, with belonging now at the center. A recent 2025 report underscores a growing emphasis on student well-being, community, and engagement, signaling that expectations now extend beyond logistics to ensure students feel supported in their living environments. AI is enabling that shift by reducing administrative workload and giving teams more time to focus on meaningful student engagement.

  • Campus Safety Requires Using Every Resource Available

    Across the U.S., school and campus leaders are facing a security landscape that has changed dramatically over the past decade. Incidents on school property have increased in recent years, with several consecutive years setting record totals. According to analysis of data by CNN, dozens of shootings now occur on school grounds annually across K-12 and higher education environments.

  • Architectural Power for the Modern Campus Landscape

    For generations, an outdoor classroom only required a textbook and a patch of grass. Today, not only has the laptop replaced the printed pages, the rise of agile learning has turned campuses into study halls with students listening to lectures and researching topics from quads, gardens, and plazas. The challenge for architects and facility managers is to provide connectivity without cluttering the landscape with visual eyesores or creating safety hazards with extension cords.