About the pilot study

Background and purpose of the study

During the COVID-19 pandemic several infection control measures were implemented including school closures, which may have had consequences for learning and mental health outcomes of schoolchildren. This indicates that we need to explore alternative methods for managing the spread of infection in schools.

The use of air purifiers with HEPA filters has been suggested to reduce airborne infections, but we do not know enough about their effectiveness in school environments. Therefore, we are planning a study to investigate the extent to which air purifiers can help reduce the spread of infection in classrooms. 

During the winter season 2024/ 2025 we therefore conducted a pilot study to investigate whether it was feasible and acceptable to install air purifiers in Norwegian classrooms.The pilot study was conducted by the Centre for Epidemic Intervention Research (CEIR) at the Norwegian Institute of Public Health (FHI) in collaboration with SINTEF and selected schools in Drammen and Lier.

Implementation and data collection

The pilot study consisted of two different parts. Selected schools in Drammen participated in part 1, while one school in Lier participated in part 2.

We equipped participating classrooms with air purifiers and air quality sensors. In part 1, schools either received ceiling-mounted or portable air purifiers. All the units was active throughout all teaching hours over a period of 6 weeks. At the school in part 2, we alternated between turning the air purifiers off and on in various classrooms.

The pilot study did not entail changes to existing timetables.

The project group collected aggregated absence data from the school's absence records, data on air quality from classrooms, as well as interview data from students (part 1) via questionnaires to parents and teachers (part 1 and 2).

Results

Results showed that installing and operating both ceiling-mounted and portable air purifiers in classrooms was feasible in Norwegian classrooms. Neither teachers nor students reported any harms or disadvantages of having air purifiers in the classroom. Air purification was superior to no air purification, and portable devices were as effective as ceiling-mounted devices. Portable air purifies were thus more user-friendly.

Collection of absence data was feasible, but some inconsistencies between the schools’ own systems were found. However, it was challenging to collect consent from students’ legal guardians.

The article from this study has been published in Trials.