Assessment of Indoor Classroom Environment Quality Associated with Student Sleepiness: Pathways Towards a Sustainable Environment Through a Pilot Study

Student sleepiness during classes is a frequently reported condition that can impair performance in the teaching–learning process and is even unsustainable for health. Although the environmental quality of the classroom may affect the students’ sleepiness, studies that exhaustively investigate the relationship between indoor environmental quality (IEQ) and sleepiness levels in classrooms are lacking. To this end, in the present paper, we carried out an experimental pilot study involving twenty-seven Italian adolescent students to determine the increase in their sleepiness rate during the school period utilizing the Epworth Sleepiness Scale (ESS). The analysis was performed in a classroom in which the indoor environmental quality was monitored, including measurements of the thermal comfort, sound pressure level, illuminance, carbon dioxide (CO2) concentrations, and airborne particle concentrations (both sub-micrometric particles and PM10). Three measurement days were considered. The results showed that student sleepiness significantly increased during the school period (Day 1 p = 0.00, Day 2 p = 0.03, and Day 3 p = 0.03). This increase was observed on measurement days characterized as having both perceived higher and lower thermal comfort and even in the presence of limited exposure to airborne particle concentrations, presenting an association with the high indoor concentration of CO2 detected in the classroom (Day 1 between 978 and 3261 ppm; Day 2 between 1044 and 2338 ppm; Day 3 between 1116 and 2623 ppm), due to reduced ventilation rates and the students’ sleepiness. Thus, the findings suggest that adequate ventilation rates can limit the increase in the rate of sleepiness, indicating, from our pilot study, that recommendations of sustainable environmental practices through comprehensive feasibility studies can promote positive changes in indoor environments such as classrooms.