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  • Sean Rapley

Are You Smothering Learning Performance? Learn How To Avoid Stifling Learning in Your Classrooms

Key takeaways

• Poor ventilation leads to poor learning performance.

• Ensure new learning spaces are always mechanically ventilated.

• For existing learning spaces without mechanical ventilation, always ensure some windows are open during class time.


Learning outcomes for students can be impacted by a range of factors, and recent research indicates indoor air quality may have a significant impact on student performance.

We review the impact indoor air quality can have on student performance, review research that shows the extent of the problem, and we outline issues that designers and teachers should understand about the learning environment they design or work in.

Research on Student Performance

Research conducted by Fisk & Mendell et al[1], investigated the impact of exposure to high carbon dioxide (CO2) concentrations on student performance. They assessed CO2 exposure at three concentrations: 600, 1 000 and 2 500 ppm. They recruited 24 participants, mostly college students, who were studied in groups of four in a small office-like chamber for 2.5 hours for each of the three conditions. Ultrapure CO2 was injected into the air supply and mixing was ensured, while all other factors, such as temperature, humidity, and ventilation rate, were kept constant. The sessions for each person took place on a single day, with one-hour breaks between sessions.

The study used the Strategic Management Simulation (SMS) test to assess the decision making performance of the test subjects. The SMS test looks at a number of dimensions, such as how proactive you are, how focused you are, or how you search for and use information. The results are outlined in Figure 1.

Figure 1

Research on Classroom Carbon Dioxide Concentration in Classrooms

If high CO2 concentrations can have a significantly adverse impact on student performance, then what do we know about the prevalence of high CO2 concentrations in existing learning spaces?

Boulic et al[2], of Massey University, New Zealand carried out a survey of 20 schools in Auckland, and 8 schools in Dunedin. These schools were all provided with a wall mounted split systems, and relied on natural ventilation via operable windows. A situation not unique to New Zealand schools.

Boulic et al[2], conducted a survey of school teachers, and how they manage the indoor air quality in their learning spaces. The survey found that 45% of teachers did not open their windows, and many of the teachers relied on the wall mounted heat pump to provide ventilation, on the mistaken assumption the units also provide ventilation.

Boulic et al [2], also installed CO2 monitors within a sample of classrooms and the following CO2 concentrations were found:

1) CO2 concentrations exceeded 2000 ppm 28% of time.

2) CO2 concentrations exceeded 1000 ppm 57% of the time.

Boulic et al [2] research indicates that high CO2 concentrations in learning spaces are commonplace, with potentially significant consequences for students.

What Teachers Need to Do.

You can only work with what you’ve got, and many existing classrooms rely on natural ventilation. You should ensure some of ther windows in your classroom always remain open during class time (ideally on opposite walls to allow cross ventilation). Even small openings will help prevent CO2 levels exceeding 2000 ppm which can significantly improve learning performance.

On the bright side, existing classrooms reliant on natural ventilation present a great learning opportunity for students, and perhaps students can be empowered to manage ventilation in their classrooms.

What Designers Need to Do

Fisk & Mendall et al[1] demonstrated the importance of good indoor air quality for learning performance. Boulic et al’s[2] study demonstrated that relying on overloaded teachers to manage indoor air quality leads to poor outcomes.

With this in mind, designers should end the practice of relying on natural ventilation to maintain good indoor air quality in the learning environment. Mechanical ventilation will ensure good indoor air quality, and allows teachers to focus on what they do best.

For more information on how to design a great learning environment for your students, you are more than welcome in contacting me here.

Kind regards,

Managing Director


1. Usha Satish , Mark J. Mendell, Krishnamurthy Shekhar, Toshifumi Hotchi, Douglas Sullivan, Siegfried Streufert, and William J. Fisk , “Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making Performance”.

2. Mikael Boulic, Robyn Phipps, Chris Cunningham, Dr Khalid Arif, Dr Patrick Biggs, David Waters, Bill Trompetter, “Research project: Creating healthier classrooms for NZ primary school students

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