Updated: Nov 2, 2020
Lighting can have positive impacts on the environment; however if not carefully considered the adverse effects can easily outweigh any positive impacts.
Most lighting installations remain in place for many years (even beyond their service life), it's therefore crucial that the design is prepared consciously.
What is designed today will impact the environment for potentially 20+ years.
In this post we look at light pollution, the impacts of lighting and how we can mitigate the adverse impacts.
What types of light pollution are there?
What are the types of light pollution?
Sky Glow - This form of light pollution impacts our view of the night sky. To appreciate this impact, take a look at the sky at night within a city and then take a look in the countryside. Or take a look at the night sky above a town or city when viewed from a distance.
With the widespread usage of LEDs the sky glow above many areas has improved, due to their good upward light characteristics.
Glare - The reduction in the ability to see due to the high contrast between dark and bight areas. Glare can be classified in two forms:
Disability glare - this impairs vision and is considered dangerous
Discomfort glare - induces a feeling of discomfort
Over-illumination - This is achieved through poor design or poor policy decisions. Areas illuminated more than required providing wasted light and energy.
Light Spill - An unwanted spill light on areas that do not require illuminating. For example the spill light from highway lighting to property gardens. The term trespass shouldn't be used as it implies an unlawful act.
What are the impacts on the environment?
It's just one flood light what harm can be caused? In fact, a poorly designed light installation can have a big impact on its surroundings, whereas a good lighting system can provide benefits and remove any potential adverse effects.
Improving the fear of crime
Improving safety on the highway
Encouraging the use of sustainable transport - walking, cycling
Encourage the use of sports facilities at night
Poorly designed lighting has a host of adverse effects on the environment. In particular the impact on ecology can be huge. Check out our post on ecologically sensitive lighting designs.
Disruption to ecology - animals which sleep during the day and are active at night can be massively impacted by their night turning to day. Poor lighting is particularly harmful to bats. The ILP and Bat Conversation Trust have produced a Guidance Note (8) on Bats and Artificial Lighting in the UK - you can download a free copy here.
Human health issues - lighting can impact the human body clock and hormonal system. Colour temperatures that are cooler (blue) have the most potential for harm. The industry as a whole appears to be shifting away from colour temperatures greater than 4000K.
View of the night sky - as discussed under types of light pollution, a poor lighting system can impact our view of the night sky.
Energy usage - an over-illuminated design will use more energy than necessary. It will also require more components and raw materials having a knock on effect.
How can we mitigate the impact of a light installation on the environment and still provide the benefits?
With technological advances and the development of LEDs it has become easier to mitigate light impacts on the environment; listed below are just some of the tools we can use to reduce our impact as much as possible:
Careful selection of optics - many lantern types now come with a large number of different optics to choose from. This allows the designer to select where the light is required - need a sharp rear cut-off? No problem, there's an optic for that.
Louvres and lens covers - in some instances where the optics just don't cut it, or we require the view of the light source to be removed, we can look at the installation of a tried and tested method (shields). A shield can be fitted to the column or you can have custom shields which fit to the lantern itself. This allows for light to blocked in any direction.
Warmer colour temperature - as previously mentioned under human health, it's best to avoid the cooler colour temperatures and focus on 3000K and below - the warmer the light the better the impact on human health and the ecology.
Reduced column heights - focusing the light where required.
0% Upward Light Ratio - most LED lanterns now have a 0% ULR. Make sure they lantern is set at the horizontal and no tilts applied and you have reduced your impact on the night sky.
Dimming and part-night switch off - the usage of an area typically falls during the late hours. We can dim or switch off lanterns to ensure the right amount of lighting is provided at the right times.
Good design - a good lighting design will consider all options available to develop a solution that impacts the environment the least but also provides purposeful lighting.
Offset - we can offset the energy usage by contributing to carbon reduction initiatives.
Is it necessary - does the area justify lighting it?
With every lighting design prepared all of the above plus much more should be considered to ensure its lasting impact is a positive one.