Due to hot arid climate in Jeddah, Saudi Arabia, occupants rely on air conditioning (AC) to provide both ventilation requirements and thermal comfort. It is believed that this total reliance on AC have also a significant effect on thermal sensation as well as cognitive performance of building occupants. Using a multi-variable multilevel statistical analysis, the effects of classroom temperature and CO2 levels on cognitive performance were estimated. Eight neurobehavioral cognitive tests were used to evaluate cognitive performance of 499 female students (16-20 years old). In addition, thermal sensation votes were collected. All participants were exposed to nine different environmental conditions, a combination of three temperature levels 20°C, 23°C and 25°C, and three CO2 levels: 600 ppm, 1000 ppm and 1800 ppm. The baseline condition levels were set at 20°C and 600 ppm. In this paper the interrelationships between the thermal sensation votes and effects of classroom temperature and CO2 levels on vigilance (Simple Reaction Test, SRT) and memory tasks (Reversal Learning, RL) are presented. The results suggested that the 'cold' thermal sensations have been linked to significant increase in 'percentage of errors' for both memory and vigilance tasks. Also, the exposure to higher CO2 levels of 1800 ppm and 1000 ppm have led to a significant increase in the 'percentage of errors' for both cognitive performance tasks compared to the baseline conditions. The study has also confirmed that the significant influence of acclimatization should not be overlooked when setting up the environmental design criteria for buildings in hot arid climates.
In the hot climate of Saudi Arabia, people living year‐round in air‐conditioned spaces are likely to develop high expectations for homogeneity and cool temperatures, becoming potentially more sensitive if thermal conditions deviate from the comfort zone they expect. This paper presents the results from a field intervention investigating the association between participants’ thermal sensations with cognitive performance in a female university in Saudi Arabia. The climatic context plays a key role in choosing Saudi Arabia, whereas the total reliance on air‐conditioners (AC) for cooling is believed to have significant effects on occupants’ perceptions of the comfort temperature. Results reveal discrepancies in the actual thermal sensations between the Saudi and non‐Saudi participants which affected their performances. “Cool” and “Slightly Cool” sensations versus neutral were associated with significant lower percentage of errors and significant higher speed for all participants independently of any association with ethnicity and acclimatization. The estimates remained significant even after adjusting for ethnicity and the number of years spent in the country and the set temperature of AC at home. Implications of the study suggest a preference for staying cool when working independently of acclimatization status.
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.
During the past few decades and in the rapidly developing tropical climates of Asia-Pacific regions and the hot arid climates of the Arabian Peninsula, engineers have focused on creating comfortable indoor environments inductive to productivity in an aim to promote "sustainable development" with a resultant heavy reliance on HVACs for ventilation. Research on office performance has shown that occupants' exposures to inadequate ventilation rates and to elevated or very low temperatures attribute to a higher prevalence of employees' illnesscaused absence; which, in a sense, is reflected in their income. However, scare data is available regarding to which extent the working environment has affected employees' income particularly that the effect of temperature, thermal comfort and quality of air from the HVAC systems used in the Arabian Peninsula is less understood. This study is investigating the impact of the working environments on employees' economic status in non-temperate climates. A field study of thermal comfort was conducted in Saudi Arabia, during the fall of 2013, in which over 800 workers responded to a questionnaire while simultaneous physical measurements were taken. The results suggest that employees in Saudi Arabia became highly accustomed to air conditioners; perceiving temperature 22°C as the comfortable temperature compared to 25°C. However, their productivity has been impaired and their absenteeism rates have doubled with an equivalent salary deduction of 1/8 of the typical payment per annum.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.