Light is the major synchronizer of circadian rhythms to the 24-hour solar day. Compared to the visual system, the circadian system requires more light to be activated and is more sensitive to short-wavelength light. Without access to daylight, or electric lighting providing a comparable amount, spectrum, distribution, duration, and timing, human health and well-being may be compromised. This may be particularly true for those confined indoors, such as patients in hospitals and residents in care facilities. Architectural and design features, including window size, surface reflectances, and furniture placement, impact circadian stimulus levels. This paper details results of simulations used to determine the percentage of days that patients would receive a minimum level of circadian stimulation as a function of different window-to-faç ade ratios, surface reflectances, and latitudes.

No abstract

No abstract

No abstract

A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in Andalusia and the evolution of CO 2 concentration during school hours through in situ monitoring. Pressurization and depressurization tests were performed in 42 classrooms and CO 2 concentration was measured in two different periods, winter and midseason, to study the impact of the different levels of aperture of windows. About 917 students (11-17 years of age) were surveyed on symptoms and effects on their health. The mean n 50 values are about 7 h −1 , whereas the average CO 2 concentration values are about 1878 ppm, with 42% of the case studies displaying concentrations above 2000 ppm with windows closed.