Light pollution – a term used to describe the effect of illuminating the night sky with too much artificial light – has dangerous repercussions for both humans and animals. Not only does it gravely disrupt the breeding and migratory habits of nocturnal animals, it also leads to insufficient melatonin in humans; melatonin is the hormone that helps us sleep and regulate cortisol levels.

In response, the ‘dark-sky’ movement is gathering momentum as a possible panacea for the detrimental impacts of light pollution.

“Light pollution is having really serious impacts on wildlife and on human health,” says Dr Kellie Pendoley, scientist and founder of Pendoley Environmental. “Technically, light is a form of radiation but it’s never been recognised or managed that way.”

Dr Pendoley, who has spent 30 years studying the impacts of light pollution, helped draft the federal government’s National Light Pollution Guidelines for Wildlife, which now aim to protect all species.

Light pollution also impacts our heritage, she explains. “First Nations people are the oldest astronomers on earth and they tell their stories through the stars. Limiting the visibility of stars limits the ability of First Nations people to share their stories – that’s an important cultural connection we need to preserve.”

Dr Pendoley works with design teams from around the globe, sharing methods of measuring, monitoring and modelling light – not just on a local level but on a landscape scale up to 100 kilometres away. “I encourage every architect and designer to look beyond their building’s footprint – light scatters into the atmosphere and that is what creates biological implications.”

She advises restraint in lighting design. “Obviously, the more lights you have, the more energy you burn and the more greenhouse gases you emit,” she says.

“When it’s well designed, lighting can be both beautiful and muted. I’ve seen exemplars around the globe that prove built structures can be illuminated in subtle ways that make them look and feel elegant. Big, bright lighting comes at a cost, aesthetically and environmentally.”

Toby Murdoch of Ashburner Francis calls on all stakeholders in the built environment to help minimise light pollution. “Regulators, clients, architects, lighting designers, and contractors should all be working in unison to bring about real change,” he says.

An electrical engineer, he has put together a list of four simple, yet effective ways to reduce light pollution.

1. Select the right light fittings

For lighting large outdoor areas such as sporting stadiums, Murdoch recommends ‘flat-tilt’ asymmetric floodlights to ensure the light lands where it’s most needed.

“Traditional floodlights only provide symmetrical lighting so the fitting has to be tilted to target the area you wish to light. A significant portion of that light will go above the horizontal plane – directly into the sky.” This leads to wastage of energy and light pollution of the night sky.

Closely monitoring ‘light spill’ (i.e., sending light to locations where it’s not needed) and ‘light glare’ (i.e., light that causes discomfort or impedes people’s ability to navigate a site) is, of course, essential.

2. Minimise blue spectrum lighting

Commenting on the impact of LED lighting on light pollution, Murdoch says, “When LED lighting was first introduced, the energy efficiency of bright-white light was considered far greater than warmer colours.” Unsurprisingly, that efficiency/affordability made white-coloured LEDs more popular.

But white light is problematic because it has a degree of blue spectrum within it. “Any light source that contains an element of blue will likely be more reflective than warmer colours,” he says. White LEDs, therefore, create significant ‘sky glow’.

Dark-sky advocates would prefer that designers opt for LEDs with amber and/or warm-white colours that are less reflective and cast less ‘sky glow’.

3. Adjust illumination

Murdoch encourages architects to stay abreast of emerging technologies designed to help minimise wasteful lighting.

“Motion sensors are now available that can brighten street lighting as you reverse out of your driveway – then incrementally brighten the next sequence of lights before you approach them,” he says. That kind of technology can take a light from 20% illumination to 100%, as and when required. “That’s up to an 80% energy saving but also limits unnecessary light pollution from adversely impacting surrounding wildlife.”

Additionally, architects could consider simple strategies such as automatic late-night dimming for facades and exterior spaces that may not require full illumination from dusk till dawn.

4. Challenge convention

Murdoch doesn’t believe that fully illuminating large outdoor spaces acts as a deterrent to troublemakers. “I’d like to see architects press their lighting designers to look for alternate ways – that don’t rely on excessive light pollution – to provide passive surveillance for their projects.”

Design teams are often reluctant to pull back on lighting. “I think sometimes we are scared of not providing enough light, so we provide too much! We need to be braver and embrace the shadows.” However, landscape architects are easier to convince when it comes to designing with dark-sky goals because they are well informed and receptive to challenging the status quo when it comes to lighting, he adds.

Image: https://www.linkedin.com/pulse/20141114131938-6348860-eliminating-star-stealing-sky-glow-one-led-streetlight-at-a-time/

Branko Miletic

Is-artificial-light-polluting-the-night-sky-1732010262.png

Let’s connect!