Association between Outdoor Ambient Illuminance and Elderly People’s Moods in a Care Home

Daylight has potential to stimulate individual’s sensations and feelings. Older people who live in care homes should have some sense of outdoor daylight that might influence their moods. This paper describes a pilot study that investigates the association between the outdoor ambient illuminance and elderly people’s mood changes in a care home environment while controlling other contributory factors, such as outdoor temperature, occupant age, gender and medical conditions (e.g. dementia and blindness). Real world field data was collected from an existing care home. Environmental data (outdoor illuminance and temperature) was collected by installing outdoor data loggers on the roof top of the care home. Demographic and physiological information of the occupants were collected from care home records. Care home staff rated occupants’ moods on a Likert-type scale composed of three quantifiable response modes: numerical rating scale (NRS), visual analogue scale (VAS) and faces rating scale (FRS). Ordered logit (OLOGIT) model, suitable to develop correlation between ordinal dependent variables (i.e. mood) and continuous data (i.e. illuminance) are used. The analysis shows, assuming all other explanatory variables remain constant, the probability of a better mood increases with the increase of outdoor illuminance (p-value=0.022). However, in a very hot/cold day the probability of a better mood could be decreased under the same outdoor daylight level.