World Park Congress, 2014, Sydney Australia
Presentation and Documents on the Impact of Light on the Ecosystem and Human Health
Current luminaires deliver various shades of white light. However white light, when used during the night, can disrupt the circadian rhythm and alter the nocturnal environment on which most life depends. It fundamentally changes the environment into one for which we have not adapted biologically. This undermines our natural physical and mental health mechanisms.
We had three goals for attending the World Park Congress:
A lighting policy could be based on the following statement.
Whereas, artificial light at night fundamentally changes the ecology of the night and undermines
the effectiveness of natural biological mechanisms that maintain plant, animal and human health.
The ecological impact of artificial light at night shall be minimized by limiting its spectrum,
brightness, extent and schedule to rational thresholds based on ecological and biological studies.
There are four key attributes for a luminaire that minimize its impact on the environment.
1. Illumination that affects only the area needed to be lit.
Achieved with full cut-off fixtures (fully shielded) to prevent any
direct light above the horizon and restricts the amount of light
within 80 to 90 degrees of the nadir. This also reduces glare
and light trespass.
2. Minimum practical level of illumination (brightness).
This reduces glare from the luminaire, reduces the amount of
scattered light from the illuminated area, and it saves electricity.
By removing glare good visibility can be attained at significantly
lower illumination levels.
3. The colour of light should avoid blue wavelengths.
Although white light is suitable for indoor daytime illumination, at
night it is disruptive to normal biology. This has been shown to contribute
to the erosion of human health and mental well-being and alters the behaviour of animals and plants.
4. The illumination should be turned off when it is not needed.
Lights should be turned off, or significantly reduced in brightness
when businesses are closed, or when most people have gone indoors. “Security lighting” serves no purpose if no one is around to see a felony in progress. Indeed it simply puts property on display for vandals and thieves.