cpd paper light for health and wellbeing
TRANSCRIPT
Alan Grant, Design and Development Director, DW Windsor
Light for health and wellbeing
CPD PAPER
The day-night cycle
Artificial light
White LED light sources
Where ignorance is bliss (tis folly to be wise)Thomas Gray 1716-1771
Donald Rumsfeld, US Secretary of Defence 2001-2006
How do LEDs affect health?
What we’ve learnt in the past two decades:
• A newly discovered photoreceptor detects optical radiation but doesn’t contribute to image forming
• Photoreception leads to vision & to effects on human physiology, mood and behaviour
• Non-visual photoreception; connection to circadian regulation, melatonin
• Non-visual effects depend on the spectrum, intensity, duration, timing and temporal pattern of the light exposure
What does this mean for humans?Professor Russell Foster, Professor of Circadian Neuroscience and Head of the Department of
Ophthalmology at Oxford University
• Poor circadian regulation causes loss of attention, memory impairment, failure to process information, and reduced cognition and creativity.
• Compromised biological functions and melatonin suppression lead to immune system suppression, increased likelihood of cancer and cardio-vascular disease, diabetes, metabolic suppression and obesity.
• Mood instability, anxiety and increased risk of mental illness have also been linked.
• Non-visual effects depend on the spectrum, intensity, duration, timing and temporal pattern of the light exposure
What do lighting organisations say?
• Clarifies the definition of what is referred to as Blue Light Hazard
• Recognises light sources emitting primarily blue light are a cause for concern for exposure to children’s eyes
• Recognise public concern over non-visual influences of blue light on human health
• Presents current understanding from leading lighting research scientists
• Urges the industry to recognise the current limitations in our knowledge
• Recognises the need for additional studies
What’s in a name?
Human Centric LightingLighting that can benefit the biological, emotional, health, or wellbeing of people. Lighting Europe
Circadian Lighting
Bio-dynamic LightingLight that has a physiological effect on the body.
Nutritional LightThe importance of nutritional light on the wellbeing of people. Good light Group
Outdoors
The colour temperature question…
• Have we settled on 4000K by accident?
• With efficacies across all colour temperatures improving, should this change?
• Are there applications where different colour temperatures are appropriate in different circumstances at different times?
• How do our lighting strategies affect flora and fauna?
Spectral Power of white LEDs
Daylight LEDs
Using violet LEDs and phosphor chemistry, blue content is reduced.
Effect of daylight LED on visual comfort, melatonin, mood, waking performance and sleep
Daylight LEDs
Moonlight LEDs
Trade-offs
Efficacy reduces as:
• Colour temperature gets warmer
• CRI improves
Dynamic lighting
International Lighting Policy
• Outdoor lighting curfews• Colour temperature
restrictions: 3000K max, 2700K & 2400K
Italy• No light above horizontal
The first world atlas of the artificial night sky brightness P. Cinzano, F. Falchi, C.D. Elvidge
7.5 million streetlights in the UKFrédéric Tapissier
Summary
• Warmer colour temperatures
• Dynamic lighting & control
• Shields as standard in residential areas?
With good lighting, everybody wins
