The aim of the study was to determine whether indoor lighting and colour would have any systematic impact on the mood of people working indoors. Earlier studies have mostly focused either on light, colour or windows in laboratory settings. The present study was carried out in real work environments at different seasons and in countries with different latitudes. A total of 988 persons completed all parts of the study. In the countries situated far north of the equator there was a significant variation in psychological mood over the year that did not occur in the countries closer to the equator. When all four countries were considered together, it became evident that the light and colour of the workplace itself also had an influence on the mood of persons working there. The workers' mood was at its lowest when the lighting was experienced as much too dark. The mood then improved and reached its highest level when the lighting was experienced as just right, but when it became too bright the mood declined again. On the other hand, the illuminance as measured in objective terms, showed no significant impact on mood at any time of the year. The relationship between mood and the distance to the nearest window was bimodal. The results also indicate that the use of good colour design might contribute to a more positive mood. It is suggested that in future research light and colour should be studied as parts of the more complex system making up a healthy building.

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Wind power projects frequently face public opposition during the siting process. A deeper understanding of social factors has therefore been called for. Based on psychological theories, the present research was initiated in order to study the relative importance of individual aspects related to visual perception and attitudinal factors in public intention to oppose local wind turbines. In an empirical study, 80 people assessed the visual characteristics of wind turbines on site and rated their emotional state. They also completed a questionnaire covering attitudes towards the turbines, perception of significant others' opinions of local wind turbines, and perceived possibilities to oppose as well as intention to oppose local turbines. Moreover, socio‐demographics, factors related to the place of residence and general attitude towards wind power, were investigated. In a multiple regression analysis explaining 50% of the variance, it was found that intention to oppose was related to only a few perceptual and attitudinal factors, i.e. the perceived unity of the environment, the personal attitude towards the effects of wind turbines on landscape aesthetics and recreation, and the general attitude towards wind power. Of minor importance was the attitude towards the effects of wind turbines on people's daily quality of life. It seems important to involve the public in the discussion of how wind power installations can be integrated into the landscape without threatening the visual beauty and the recreational value of the natural and cultural environment. Moreover, social intervention is required to promote positive attitudes towards wind turbines. Copyright © 2007 John Wiley & Sons, Ltd.

In working environments all over the world, fluorescent tubes are by far the dominating light source. Still, there have been very few studies on the impact of the non-visible flicker from fluorescent tubes. The purpose of the study was to compare the impact on subjective well-being, performance and physiological arousal of fluorescent light powered by conventional and high-frequency ballasts. Thirty-seven healthy males and females were subjected to either condition in a laboratory office on two separate occasions with 1 week in between. Although the methodology was quite extensive, only a few general effects were observed. However, when the light was powered by the conventional ballasts, individuals with high critical flicker fusion frequency (CFF) responded with a pronounced attenuation of EEG alpha waves, and an increase in speed and decrease in accuracy of performance. These results may be understood in terms of heightened arousal in the central nervous system in response to the pronounced light modulation caused by the conventional ballasts. In order to alleviate this potential stress source, it is recommended that fluorescent lighting be powered by electronic high-frequency ballasts of good quality.

Owing to the prevalence of fractal patterns in natural scenery and their growing impact on cultures around the world, fractals constitute a common feature of our daily visual experiences, raising an important question: what responses do fractals induce in the observer? We monitored subjects' EEG while they were viewing fractals with different fractal dimensions, and the results show that significant effects could be found in the EEG even by employing relatively simple silhouette images. Patterns with a fractal dimension of 1.3 elicited the most interesting EEG, with the highest alpha in the frontal lobes but also the highest beta in the parietal area, pointing to a complicated interplay between different parts of the brain when experiencing this pattern.

BackgroundSeasonal variations in physiology and behavior have frequently been reported. Light is the major zeitgeber for synchronizing internal circadian rhythms with the external solar day. Non-image forming effects of light radiation, for example, phase resetting of the circadian rhythms, melatonin suppression, and acute alerting effects, depend on several characteristics of the light exposure including intensity, timing and duration, spectral composition and previous light exposure, or light history. The aim of the present study was to report on the natural pattern of diurnal and seasonal light exposure and to examine seasonal variations in the circadian change of melatonin and cortisol concentrations for a group of Swedish office workers.MethodsFifteen subjects participated in a field study that was carried out in the south of Sweden. Ambulatory equipment was used for monthly measurements of the daily exposure to light radiation across the year. The measurements included illuminance and irradiance. The subjects collected saliva samples every 4 h during 1 day of the monthly measuring period.ResultsThe results showed that there were large seasonal differences in daily amount of light exposure across the year. Seasonal differences were observed during the time periods 04:00–08:00, 08:00–12:00, 12:00–16:00, 16:00–20:00, and 20:00–24:00. Moreover, there were seasonal differences regarding the exposure pattern. The subjects were to a larger extent exposed to light in the afternoon/evening in the summer. During the winter, spring, and autumn, the subjects received much of the daily light exposure in the morning and early afternoon. Regarding melatonin, a seasonal variation was observed with a larger peak level during the winter and higher levels in the morning at 07:00.ConclusionsThis study adds to the results from other naturalistic studies by reporting on the diurnal and seasonal light exposure patterns for a group living at a northern latitude of 56° N, with large annual variations in photoperiod length. It seems to be seasonal variation in the lighting conditions, both concerning intensities as well as regarding the pattern of the light exposure to which people living at high latitudes are exposed which may result in seasonal variation in the circadian profile of melatonin.

Indoor lighting is facing a massive retrofit to LED lighting. Research is needed to assess whether LED-based lighting can promote energy efficiency, boost visual comfort and support biological functions. This field study considered the lighting of four identical classrooms in an upper secondary school in Helsingborg, Sweden. Two classrooms were fitted with state-of-the-art ceiling pendants containing T5 fluorescent tubes and that had a direct/indirect light distribution (the control rooms). The other two classrooms were fitted with an experimental LED indirect lighting system (the experimental rooms). In the classrooms, 72 students aged 17–18 years performed their usual educational activities over a whole academic year. The light environment, electricity consumption, and students’ mood, light perception and saliva cortisol concentration were monitored. The two lighting systems produced only marginal differences. Overall, the experimental rooms were slightly preferred but achieved only small energy savings due to high parasitic losses.

This study investigated the extent to which perceived physical and social-environment qualities of supported housing facilities (SHF) account for variations in the perceived quality of life of people with severe mental illness (SMI). Based on a user-centered approach, people with SMI (N = 72) appraised the environment of their SHF (N = 20). Moreover, it investigated whether place attachment played a role in the relationship established between the environment of SHF and users' quality of life. Perceived physical and social-environment qualities predicted quality of life. Together the two factors accounted for approximately 32% of quality of life variance. Furthermore, attachment to place mediated this relationship. Implications for future planning of psychologically supportive facilities for this vulnerable group in society are discussed.