Identification of spectral distributions in light-dosimetry data: Methodology and application to an intervention field study

Modern life in predominantly indoor environments has led to a profound alteration in the amount, spectral distribution and pattern of light humans are exposed to daily. Given the role of light in health and well-being, and to understand how modern living can be better aligned with human biology, light-dosimetry plays an important role in characterising personal light exposure across individuals. To consider the spectral distribution in light-dosimetry and evaluate the variability and effects of individual ‘spectral diets’, a sufficient spectral resolution is required. In this paper, we present selected analyses of spectrally resolved light-dosimetry data that were collected during a dynamic lighting intervention study in Iceland. Unsupervised clustering was performed to process the collected data, and clusters were classified using various reference spectra. The results not only show that different spectral types can be sufficiently well discriminated, but they can also be used to verify the experimental conditions effectively experienced by participants and to start evaluating the effect of other factors (e.g. daylength, or impact of time outside experimental conditions). Taken together, our findings highlight the benefits and potential uses of spectrally resolved light-dosimetry, which will hopefully contribute to, first, better understand and, ultimately, improve our contemporary relationship with light.