Lodz, Poland, 14 July 2026
Schools are not only places of education; they are also environments in which children and young people spend a significant proportion of their day. Ensuring good air quality in school buildings is therefore an important part of protecting health and well-being and creating conditions that support effective learning.
Classrooms pose a particular challenge in this respect. Occupancy levels can be up to four times higher than those typically found in office buildings. Large numbers of students spending extended periods in enclosed spaces can lead to a rapid rise in carbon dioxide (CO2) concentrations, poorer air quality and an increased risk of infection transmission.
As Professor Wojciech Hanke of the Nofer Institute of Occupational Medicine in Lodz explains: “Research clearly shows that elevated CO2 concentrations can cause fatigue, drowsiness and headaches. They may also affect cognitive performance, slow down the learning process and increase the number of errors made when completing school tasks. Children are more susceptible to respiratory infections, while crowded indoor spaces increase the risk of viruses and bacteria spreading. It is also important to remember that students’ needs regarding thermal comfort and indoor environmental quality may differ from those of adults. Students generally perform better in slightly cooler environments than office workers. Temperature, air quality, lighting and acoustics all work together to shape a child’s learning environment.”
Findings from IAQ measurements in Lodz schools
As part of the K-HEALTHinAIR project, researchers monitored CO₂ concentrations in 14 upper secondary schools in Lodz. The study was conducted during the autumn and winter of 2023–2024 and analysed average CO2 concentrations at the end of morning lessons and during the first longer break of the school day.
The measurements point to a significant issue with classroom ventilation. In six of the schools studied, morning CO2 concentrations reached levels close to 2,000 ppm. During the first longer break — the main school break — CO₂ levels were only slightly lower.
Only three of the 14 schools recorded CO2 concentrations below 1,000 ppm, the threshold adopted for the purposes of the analysis. Moreover, in 10 schools, the 1,000 ppm threshold was exceeded in more than 80% of measurements. Conditions improved only marginally during the main break.
These findings suggest that current classroom ventilation practices may not be sufficient to maintain adequate air quality during lessons.
Simple Measures Can Improve Learning Conditions
The preventive measures proposed as part of the project are straightforward and can easily be incorporated into schools’ daily routines. Regular and effective airing of classrooms is essential — before lessons begin, during morning classes and during the first extended break.
Bringing fresh air into classrooms helps to reduce CO2 concentrations and the number of airborne microorganisms. In turn, this may help students to concentrate better, improve their comfort and contribute to a healthier and safer school environment.
The findings of the K-HEALTHinAIR project underline the importance of air quality as a key component of a healthy educational environment. Regularly airing classrooms is a simple measure that can bring tangible benefits to students, teachers and the wider school community.
More information about the K-HEALTHinAIR project, together with materials and resources developed as part of the project, is available at: www.k-healthinair.eu.