Influência da temperatura de cor da luz no desempenho e sensações de alunos em baixa latitude

Abstract

This research assesses the influence of correlated color temperature (CCT) of artificial light and the integration with daylighting on academic students’ performance and sensations, in warm climate in low latitude (5,84 S, 35,20 W). The issue was motivated by the fact artificial light interferes in person's circadian cycle, which regulates sleep, alert, appetite, and other conditions. Such biologic clock is related to the daylight CCT hourly changes, from yellow at sunrise and sunset, to white direct sunlight and light-blue overcast daylight. The artificial light does not to match the sun’s own color shifts throughout the day and consequently disturbs the cognitive performance, attention, visual comfort and wellbeing sense. This research questions similar effect in low latitude, with abundant daylight availability, acknowledging the fact the literature regards, majority, light conditions in medium and high latitudes. The research procedures consist in assessing performance and sensations of volunteers, academic students, through test and questionnaire, during three periods: morning, afternoon and evening. Toulouse-Piéron's Test assessed attention and perception, measuring the speed and accuracy of a simple task. A following questionnaire was applied in order to quantify the self-declared sensations of lighting comfort, attention, relaxing and environment comfort, varying from null to five scale. Three different CCT fluorescent lamps available in the market were tested in a classroom, yellowish white (3000K, warm), bright white (4000K, neutral), blueish white (6500K, cold), integrated and non integrated with daylighting during morning and afternoon. The registers were statistically analyzed using the analysis of variance (ANOVA) and ordinal logistic regression, identifying morning as the only period influenced by CCT variations. The comparison among the three periods resulted in a tendency of blueish white light (6500K, cold), mainly when integrated to daylight, improving performance and comfort, attention and relaxing.