UCL Institute for Environmental Design and Engineering


Karen van Creveld

Measuring real daylight exposure afforded by various architectural environments and the implications for our health and wellbeing

The introduction of functional electric lighting approximately 100 years ago initiated a fundamental transformation in the design of our built environments and hence, in our relationship to daylight. Whilst we evolved as a diurnal species, daylight availability is no longer a defining condition for human activity and consequently our physiological and behavioural functions are no longer aligned to the natural rhythmic light and dark cycles resulting from the daily rotation of the earth. We now spend increasingly more time indoors during daytime hours under artificial lighting that has been designed to satisfy our visual needs only. Moreover, we are exposed to increasingly fewer hours of true darkness at night.

Investigations about the impact on our health and wellbeing associated with having moved from a bright, dynamic exterior lit daytime environment to a static, low brightness indoor environment is gathering momentum. This field of research has intensified over the past twenty years because of recent revolutionary discoveries about the physiology of the human eye and brain. Whilst we have for many years presumed that light may impact humans over and above the visual system, scientific research is now beginning to decipher the physiological and neural mechanisms that lie behind these processes.

The aim of my research is to understand the actual daylight exposure experienced by various human populations in a wide range of typical working environments found in our current urban context. Daylight availability within an array of architectural settings will be quantified by recording the spectral composition, timing, distribution and intensity and participants’ personal daylight exposure within their working environments will be recorded via wearable light sensors. A series of qualitative questionnaires will be undertaken to understand the impact of daylight exposure on behaviour such as sleep quality, daytime fatigue and alertness. These data will be analysed to provide a scale of daylight exposure potentials afforded by different architectural working environments. This work will contribute to the body of emerging knowledge about our non-image forming lighting needs and the type of lighting required to support our long-term health and wellbeing.