Daylight and health: A review of the evidence and consequences for the built environment

Daylight has been associated with multiple health advantages. Some of these claims are associations, hypotheses or beliefs. This review presents an overview of a scientific literature search on the proven effects of daylight exposure on human health. Studies were identified with a search strategy across two main databases. Additionally, a search was performed based on specific health effects. The results are diverse and either physiological or psychological. A rather limited statistically significant and well-documented scientific proof for the association between daylight and its potential health consequences was found. However, the search based on specific health terms made it possible to create a first subdivision of associations with daylight, leading to the first practical implementations for building design

Discomfort glare and time of day

There are strong reasons to suspect that glare sensation varies with time of the day. This study was designed to test whether such a relationship exists. Thirty subjects were exposed to an artificial lighting source at four times of the day. The source luminance was progressively increased and subjects were required to give Glare Sensation Votes (GSVs) corresponding to the level of visual discomfort experienced. Glare indices were calculated for every reported GSV, and results were statistically analysed. The findings indicated a tendency towards greater tolerance to luminance increases in artificial lighting as the day progresses. This trend was found not to be statistically related to the possible confounding variable of learning, providing evidence of an effect of time of the day on glare sensation

Lighting and daylighting for visual comfort and energy efficiency

Light influences the daily rhythm and well-being of humans in a physiological, psychological and biological way. Light doesn’t only enable humans to see; beside the visual rods and cones the human eye also contains (recently discovered) non-visual photoreceptors (Berson et al., 2002). Supported by light perception, the human biological clock system tells the human body when to regulate multiple body functions such as body temperature, sleep patterns, cognitive performance, mood, well-being, and the release and production of hormones. Compared to the sensitivity of the visual system (V), the maximum effect of the non-visual system (C) is shifted towards the shortwave radiation and has its peak in the blue part of the spectrum

Effecten van verlichting

Zonder dat we er ons bewust van zijn, heeft licht effect op uiteenlopende processen in ons lichaam. Zonder licht kunnen we niets waarnemen en daarnaast hebben we licht nodig om processen in ons lichaam te sturen. Licht zorgt ervoor dat we kunnen zien en dat onze biologische kiok geprikkeld wordt en het heeft daardoor invloed op bijvoorbeeld onze werkprestaties. In dit hoofdstuk staan de laatste ontwikkelingen over licht en verlichting in kantoren

Substances in the indoor air and house dust of dwellings

In de lucht van zestig woningen in Groningen zijn de concentraties vluchtige organische stoffen (VOS), stikstofdioxide, koolmonoxide en kooldioxide gemeten. In de meeste woonkamers werden de (gezondheidkundige) advieswaarden voor deze stoffen niet overschreden. De advieswaarde voor de concentratie van totale VOS werd in de winter in vijf woningen overschreden, voornamelijk veroorzaakt door de hogere concentraties limoneen. Deze stof zit onder andere in veel luchtverfrissers en schoonmaakmiddelen. De advieswaarde voor de concentratie stikstofdioxide is alleen in specifieke situaties overschreden, zoals in keukens van woningen met een afvoerloze geiser. In de meeste woonkamers is geen of zeer weinig koolmonoxide gemeten. In de winter is in ongeveer de helft van deze Groningse woonkamers op enig moment de toetswaarde voor de kooldioxideconcentratie overschreden. Dit betekent dat er kortere of langere tijd onvoldoende luchtverversing was. In het onderzoek zijn ook de concentraties gemeten van een aantal verbindingen in huisstof. Voor polycyclische aromatische koolwaterstoffen (PAK's) en een aantal metalen waren de concentraties beneden de advieswaarden. Lood in huisstof zou in een paar van de onderzochte woningen wel kunnen leiden tot een gezondheidsrisico voor kinderen. Dit blijkt uit onderzoek van het RIVM en TNO, in opdracht van het ministerie van VROM/directie Risicobeleid en de VROM-Inspectie. Dit onderzoek is in Groningse woningen uitgevoerd en is niet representatief voor Nederlandse woningen. Over het algemeen zijn de resultaten toch in overeenstemming met ander recent onderzoek in Nederlandse woningen.The concentrations of volatile organic compounds (VOCs), nitrogen dioxide, carbon monoxide and carbon dioxide were measured in the indoor air of sixty dwellings in Groningen, the Netherlands. The health-based guidelines for these compounds were not exceeded in the majority of the living rooms. The guideline for the concentration of total VOCs was exceeded in five living rooms in the winter. This was primarily caused by the higher concentrations of limonene in these living rooms. This substance is a common constituent of air fresheners and cleaning products. The guideline for nitrogen dioxide concentrations was only exceeded in specific situations, such as in kitchens with unvented gas water heaters. In the majority of living rooms no or very little carbon monoxide was measured. The guideline for carbon dioxide concentrations was exceeded at some point in approximately half of these living rooms in Groningen. This means that for a certain period of time there was not enough ventilation in these rooms. The concentrations of a number of substances in house dust were also measured during this study. The concentrations of polycyclic aromatic hydrocarbons (PAHs) and a number of metals were below the guidelines. However, lead in the house dust of a couple of dwellings could form a potential health risk for children. These are the findings of research carried out by the National Institute for Public Health and the Environment (RIVM) and TNO, and commissioned by the Ministry of Housing, Spatial Planning and the Environment (VROM), Environmental Safety and Risk Management Directorate and the VROM-Inspectorate. This study was carried out in Groningen and is not representative for Dutch dwellings. Nevertheless, the results are generally in agreement with those of other recent studies in Dutch dwellings.VROM-Inspecti

Daylight contribution to an artificially lit football field

Sports fields all over the world have to fulfil certain requirements defined for light conditions.\u3cbr/\u3eEspecially for the football industry these rules are very strict. Daylight has never been studied for meeting those requirements, although it has the possibility to reduce energy costs and increase visual comfort. This study investigated potential daylight contribution to a currently artificially lit sports field. As a real world example, the Philips Stadium, home of football club PSV, in Eindhoven, the Netherlands, is chosen to model, validated with on-field measurements. A model in DIALux was used to simulate a football season and focus on what the Union of European Football Associations (UEFA) has required, such as illuminance levels, uniformity and glare. Results indicate that daylight always fulfils a few of the requirements, although there are only a few situations in which all are fulfilled.\u3cbr/\u3e\u3cbr/\u3e\u3cbr/\u3e\u3cbr/\u3e\u3cbr/\u3e\u3cbr/\u3e\u3cbr/\u3e\u3cbr/\u3e\u3cbr/\u3

Simulation of virtual natural lighting solutions with a simplified view

Daylight is limited in time and space. In situations where daylight is insufficiently available, virtual natural lighting solutions (VNLS), which are systems that artificially provide lighting and view comparable to those of real windows and skylights, can be promising. VNLS can turn currently unused floor space into space with daylight qualities. The space-gaining potential of VNLS in buildings can be predicted using computational building performance simulation. This paper describes the approach of modelling VNLS with a simplified view, using the Radiance tool to evaluate the lighting performance in a reference office. The VNLS are modelled as arrays of small light sources resembling the sky, the horizon and the ground. The simulation results show that VNLS with wide beam angles generally offer a better uniformity and a larger percentage of sufficiently lit workplane area compared to those obtained with real windows under overcast sky conditions, while the discomfort glare remains comparable to that received from real windows