This briefing highlights the serious impact of light pollution emitted by digital advertising screens including the impact on biodiversity and the environment, on people’s health, and what can be done about it using local and national policy and legislation.

Find out more information on the specific impacts of artificial lighting on people’s health and wellbeing from LightAware

What is Light Pollution?

The inappropriate or excessive use of artificial light – known as light pollution – can have serious environmental consequences for humans, wildlife, and our climate. 80% of the world’s population live under ‘skyglow’ and almost no one in the UK can experience a natural night sky from where they live. Studies also show that the world got 2% brighter every year from 2012 – 2016

LED lighting in particular can be bluer, more intense, and have a harsh flicker whether visible or not. Exposure to LED lighting  is particularly harmful to humans and wildlife, and outdoor lighting with high blue light content is more likely to contribute to light pollution because it has a significantly larger geographic reach than other lighting. Unfortunately, LEDs are used for most outdoor lighting, screens and other electronic displays, creating abundant blue light

Digital advertising screens also use this type of LED light creating even more unnecessary light pollution which can have serious consequences for local biodiversity and human health. 

Map showing the distribution of light pollution across the world (image Pixabay).

Impact on biodiversity and the environment

There is growing evidence of the negative impact of artificial light pollution on species and the disruption of ecosystems which has long been a concern for conservationists. 

Plants and animals depend on the Earth’s daily cycle of light and dark to govern life-sustaining behaviors such as reproduction, nourishment, sleep and protection from predators. Increased Artificial Light at Night, known as ALAN, is directly linked to measurable negative impacts on wildlife such as bats, birds, insects, reptiles, amphibians, mammals, and plants.

Impact on insects– Insects are vital to ecosystems
– Many of our UK invertebrates are national priority species
Artificial light affects mating, feeding, navigation and development, for example in moths
– Light pollution directly contributes to the decline of many insect species.
Impact on birds– Light pollution affects migratory birds by disrupting their natural movement patterns, or causing them to mate too early, leading to declining populations
– Artificial light can cause nocturnal birds to wander off course and become exposed to danger
Impact on bats– Artificial light near a bat roost can prevent bats from emerging to feed at the right time, limiting their chances of survival
– Some bats avoid brightly lit areas, and at the same time their prey is attracted to these areas, so the bats miss out on the best feeding grounds
– Lighting near a bat roost is likely to contravene legislation as both bats and their roosts are protected by law in the UK. Therefore, planning for digital advertising screens needs to take this into consideration.

Unnecessary artificial light uses large amounts of electricity and therefore contributes to greenhouse emissions and climate change. Lighting that emits too much light or shines when and where it’s not needed wastes a lot of energy and has huge economic and environmental consequences

Adblock Leeds found that a single digital billboard may use as much energy as 37 UK homes. In addition, there is the energy used in the manufacturing and distribution of ad infrastructure and printed materials. There is also the energy needed to supply and use the products and services that ads encourage. Advertising reportedly adds an extra 28% to the annual carbon footprint of every person in the UK. In an energy world still largely reliant on fossil fuels, advertising comes at a high carbon cost.

Reducing the amount of outdoor lighting used would save billions and cut carbon emissions. In particular the energy used to light digital advertising screens is completely unnecessary and wasteful.

Impact on people’s health

All humans are sensitive to light. The quantity and quality of light we are exposed to controls and regulates our bodies in numerous ways, not just telling us when to sleep and when to wake but also influencing our hormones, immune systems and cell regeneration.

Research suggests that artificial light, especially at night, can negatively affect human health, increasing risks for obesity, depression, sleep disorders, diabetes and some types of cancer. If humans are exposed to blue light, melatonin production can be suppressed. This can lead to sleep disorders and other health problems such as increased headaches, worker fatigue, medically defined stress and increased anxiety. In Bristol, residents who live near two large digital advertising screens, with the light shining directly into the homes of some, have reported a significant impact on their health and mobility, and quality of life.

An example of blue LED light (image Pixabay).

The negative impact of LEDs and blue light in particular on people’s health is well known in terms of discomfort and disability glare, and circadian rhythm disruption. A 2016 American Medical Association report expressed concern about people’s exposure to blue light from outdoor lighting and recommended shielding all light fixtures and only using lighting with 3000 Kelvins color temperature and below. (The most common colour temperature setting for digital displays is 6500 Kelvins, also known as D65, or more which is what most phones and television screens use.)

Many people already experience physical pain and ill health when exposed to LED and fluorescent lighting. Inappropriate light affects a large number of medical conditions, including migraine, autism, lupus, epilepsy, diabetes and cancer. People with no previous health conditions also experience adverse health effects. Symptoms can include eye pain, headaches and migraines, skin rashes, burning, dizziness and nausea. The spread of new lighting has resulted in the social exclusion of photosensitive people, who find themselves unable to access many public spaces, work or socialise and even drive in the daytime, where there are digital advertising screens. 

Glare from outdoor lighting decreases vision by reducing contrast which limits our ability to see potential dangers even in the daytime, such as pedestrians and cyclists. Aging eyes are especially affected. This is why illuminated digital advertising screens are a road safety issue and many have been refused planning permission because of their impact on drivers. These adverts are designed specifically to distract us and draw our attention which is a distraction while driving or potentially when doing any other activity which cannot be good for mental health.

A digital advertising screen in Bristol next to a motorway photographed from a car at night and in the rain showing the excessive glare (image from Twitter 2021).

What can be done?

The light pollution emitted by digital advertising screens is unnecessary and has a range of detrimental impacts on local ecosystems, people’s health as well as environmental costs. Councils should refuse applications for new digital screens and should look to phase out existing screens because of the damage they cause. 

Local authorities should develop policies to control light pollution in Local Plans which will ensure that existing dark skies are protected, and that new developments or applications for advertising screens do not increase local light pollution.

In the UK the National Planning Policy Framework (NPPF) says we should limit the impact of light pollution on nature but this is not included in guidelines around digital advertising screens nor in the ‘amenity’ and ‘safety’ grounds for refusal of planning applications for new advertisements, detailed in legislation that predates the introduction of digital screens, so cannot be used as a reason to prevent them being built. Government should ensure that local authorities are implementing Government policy to control light pollution, as set out in the NPPF and associated guidance as well as implementing the policy recommendations set out by the APPG for Dark Skies

In the meantime, there are steps that can be taken to limit the impact of digital billboards:

  • The number and brightness of lights should be kept to a minimum e.g. limit luminous intensity to 300 nits (equivalent to 300 cd/m2) during the day and lower at night to avoid glare and distraction, and limit colour temperature of lights to 3000 Kelvins.
  • Lights that emit an imbalanced spectrum of light with a high blue light component, such as LEDs, should be avoided. The majority of insects and other invertebrates are most sensitive and responsive to the short wavelength end of the light spectrum.
  • Screens using pulse width modulation instead of continuous current should not be used, to avoid creating a flicker which can affect those who are light sensitive.
  • Many lights could be switched off between midnight and 6am when few people are active, or have movement sensors,  including all decorative and advertising lighting as recommended by Buglife. 
  • Do not install digital advertising screens in public spaces where people, especially those who are light sensitive, have no choice about viewing them. 
Lighting for advertising is used excessively in cities across the world but they could just be turned off (image Pixabay).

Other Governments are taking action on light pollution by developing national plans and legislation to reduce levels. For example, in France since July 2018 all businesses have had to turn off all illuminated signs, adverts and window displays between 1am-6am and in 2019 a new national law aimed at reducing light pollution came into force.

The recent Environment Bill included a Lord’s Amendment to include light pollution as it was previously omitted and a requirement for the Government to set a national target on reducing light pollution. However, this was not moved so does not seem to be included in the final Environment Act 2021.

Watch this video on why unnecessary light pollution, including from digital advertising screens, is harming people and the planet.