Why Classrooms Have an Air Quality Problem
Schools are among the worst-ventilated buildings in many countries. Pack 25-30 students into a room designed decades ago, and CO2 can exceed 2,000 ppm within a single class period. Studies across Europe and North America consistently find that the majority of classrooms exceed the recommended 1,000 ppm threshold during occupied hours.
The Impact on Learning
The connection between CO2 and cognitive performance is well documented. Research from the Harvard T.H. Chan School of Public Health showed that cognitive function drops measurably above 1,000 ppm, with decision-making and information processing hit hardest. For students sitting exams or learning complex material, this matters enormously.
- Attention span decreases as CO2 rises above 1,000 ppm
- Test scores improve when classrooms are well-ventilated
- Absenteeism drops in schools with better air quality — fewer headaches and respiratory complaints
Health Benefits Beyond Cognition
CO2 concentration is a reliable proxy for overall ventilation. A well-ventilated classroom not only has lower CO2 but also reduces the concentration of airborne pathogens, including flu and COVID-19. Read more in our article on indoor CO2 and transmission risk.
Getting Started with School Monitoring
- Start with one monitor per classroom — wall-mounted units at student breathing height (about 1.2 metres) away from windows and doors.
- Choose a robust model — monitors with WiFi and dashboard access let facility managers track multiple rooms. See our WiFi monitor recommendations.
- Set a 1,000 ppm action threshold — when levels hit this mark, teachers should open windows or activate ventilation.
- Educate staff and students — understanding what CO2 levels mean empowers everyone to take action.
- Use data to justify upgrades — logged CO2 data provides evidence for school boards to invest in HVAC improvements.
Our CO2 calculator can estimate ventilation needs for a typical classroom based on student count and room dimensions.