Combined effects of acoustics and indoor air quality on calculation performance: a laboratory experiment and a lab-dilemma investigation

Ensuring high Indoor Environmental Quality (IEQ) in educational settings is crucial for Students performance. Within IEQ, the combined effects of different domains are highly relevant, yet the interaction between acoustics and Indoor Air Quality (IAQ) requires further exploration. While laboratory studies allow precise environmental control, their representativeness of a real classroom is often unclear due to the inability to recreate all real-world stimuli. Therefore, this study examines the combined effects of acoustics and IAQ on calculation tasks, comparing results when experiments are performed in a laboratory versus real classrooms with the same participants. Nearly 200 students participated in the laboratory experiment, which included five auditory conditions: quiet, playground noise, birdsongs, and mechanical ventilation at 160 L/s and 200 L/s. A split plot design was employed where half of the students were exposed to good IAQ while the remaining experienced poorer IAQ. Results revealed main effects only for listening conditions, heavily mediated by individual noise sensitivity. These findings partially contradict previous classroom results. A comparison between settings indicates pupils were generally faster in the laboratory. Interestingly, the most favourable condition was mechanical ventilation in the lab, but playground noise in the classroom. These results illustrate the lab-dilemma regarding discrepancies between controlled and real-world conditions. While precise causes were not definitively identified, they are hypothesised to stem from individual characteristics, highlighting a strong need for better characterisation of student-related aspects in future studies.