Combined effects of ventilation rates and indoor temperatures on cognitive performance of female higher education students in a hot climate

Abstract

Impairment in mental functions attributed to the effects of indoor air quality and thermal conditions has received considerable attention in the past decade, particularly for educational buildings where students’ cognitive performance is essential to foster learning. This study explores the combined effects of indoor temperatures and CO2 levels as markers for ventilation rates on cognitive performance among female students (16–23 years old) in Saudi Arabia. The longitudinal experiments involved nine conditions combining three CO2 concentration levels (achieved via changes in ventilation) and three temperature levels involving 499 participants, all exposed to the nine conditions. The study implemented a computer‐based cognitive performance battery with “9Button” keyboards. Univariable and multivariable multilevel regression models explored the association of indoor temperature and CO2 levels (as markers for ventilation rates) with cognitive performance after adjusting for potential confounders. Potential benefits were found on speed and accuracy of tasks of cognitive performance when indoor temperature was set between 20 and 23ºC and at CO2 levels of 600 ppm compared to higher temperatures and poorer ventilation rates and that both ventilation and thermal environmental control are important and need to be improved for achieving optimum learning conditions. Nevertheless, the results are relevant for short‐term exposures lasting no more than 2 h.

EN PRENSA. Graphical-mathematical model to estimate CO2 concentration level as an indicator of SARS-CoV-2 transmission. EN PRENSA

“…La evaluación del comportamiento del CO2, basado en la ecuación (2) se muestra en la Figura 5a, el tiempo máximo de seguridad en NV no debe exceder de 1 h y 45 min con una capacidad de ocupación del 50 % considerando 3,6 m 3 / persona. Estos resultados son similares a los informes sobre el rendimiento cognitivo en estudiantes (16 -23 años) considerando los efectos combinados de la temperatura interior y los niveles de CO2 como marcadores de las tasas de ventilación, sugiriendo un espacio adecuado: temperatura ambiental 20 -23 °C, límite de concentración de CO2 de 600 ppm en exposiciones no superiores a 2 h (Ahmed et al, 2022). Además, el rendimiento en la toma de decisiones se reduce al aumentar los niveles de CO2 (1000 -1500 ppm) en espacios similares a oficinas (Satish et al, 2012).…”

“…Además, el rendimiento en la toma de decisiones se reduce al aumentar los niveles de CO2 (1000 -1500 ppm) en espacios similares a oficinas (Satish et al, 2012). La ventilación es un marcador asociado a la productividad y a actividades cognitivas como la atención, el razonamiento y las tareas de memoria (Kapalo et al, 2018;Mundackal & Ngole-Jeme, 2020;Ahmed et al, 2022).…”

Effects of elevated carbon dioxide levels on response speed in cognitive test

“…The findings are controversial and inconsistent. Adverse effects of carbon dioxide on cognitive processes have been reported by some lab studies [4], [5], [7], [8], [11], [16], [17], [19] with fixed ventilation rates and studies [13], [14], [18], [20]with varying ventilation rates. In contrast, some studies found no statistically significant effects on cognitive performance during exposures of university students for 4.25h to CO2 levels of 500, 1000 and 3000ppm with a fixed ventilation rate of 33.3L/s per person keeping bioeffluents sufficiently low [12] and during exposures of submariners for 2.5h to CO2 levels of 600, 2500 and 15000ppm [15] with varying ventilation rates.…”

“…Response speed was widely used in previous studies as one of the key parameters to measure people's cognitive performance. Among the studies which found significant effects of CO2 on cognitive performance, some did not find significant effects of exposures to elevated CO2 levels on response speed [17], [18], some studies found that response speed significantly increased in some cognitive tasks under higher concentrations [20], and some showed decreased response speed under higher CO2 levels [6]- [8], [13], [21].…”

“…Tu [8] reported significant findings on cognitive performance for response speed; significant decreases were found in text typing when CO2 levels increased from 8000 ppm to 12000 ppm. Several studies that used validated test batteries to assess participants' cognitive performance during the exposures found significant effects [6], [16], [17], [20]. In contrast, Maniscalco's [9] study utilised a test battery Attentional Performance and showed no effects on cognitive performance at CO2 levels as high as 20,000 ppm.…”