Light pollution: risks and mitigation

By: Secom
17 de February, 2021
Reading time: 12 min

A well-lit, dazzling city is synonymous with progress, economic development and prosperity, but light pollution is a big issue in today’s society, with some very specific impacts that go way beyond not being able to see the night sky.

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What is light pollution?

We can think of it as artificial light emissions primarily from urban night lighting. The design and positioning of urban lighting often has more to do with aesthetics than functionality. This can lead to excessive lighting emissions and systems which are so inefficient that most of the light is directed towards the sky, rather than downwards in a useful direction.

Preventing light pollution

Light pollution isn’t just a problem for people – flora and fauna are also at risk. Light can be blinding for animals and can alter the biological cycles of a number of species, not to mention the environmental consequences of an excessive increase in energy consumption and higher CO2 emissions. And of course, light can make it impossible to contemplate the night sky in all its glory.

Several factors come into play when attempting to avoid and reduce light pollution. We highlight some of the most significant ones below:

  • The design, planning and installation of lights are crucial both for aesthetics (the use of street lights, spotlights or floodlights, as appropriate) and for planning and installation in public infrastructure.
  • The position and angle of lights are crucial to ensuring that light is not directed upwards. Light should always be directed downwards to reduce luminous flux.
  • Use of an appropriate power level – excessive power not only significantly increases the amount of light pollution, it entails increased energy consumption which in turn leads to excess costs.
  • Lighting times. Do cities really need to be lit all night? Most likely, the answer is no. There’s no need for every urban light to be on all the time. To ensure that light is used responsibly at historical and tourism sites, the established lighting times must be respected, and lighting should be reduced or turned off completely during less active times.
  • Warm tones are easier on the eye and should always be a first choice.

Reducing light pollution is much easier when we follow these guidelines. However, there is still a long way to go.



Current legislation on light pollution

In an effort to make street lighting more sustainable, the Spanish government passed Act 15/2010 of 10 December on the prevention of light pollution and fostering energy savings and energy efficiency with regard to lighting installations. The main aims of this legislation are as follows:contaminacion-luminica

  1. To protect the environment from light-related nuisance.
  2. To encourage good lighting that protects the health of people and of flora and fauna.
  3. To promote energy savings and energy efficiency in lighting systems to combat climate change, without negatively impacting safety.
  4. To safeguard the landscape and take all possible steps to protect the night sky.
  5. To prevent light pollution from being a nuisance in people’s homes.

Not everywhere is the same or has the same lighting requirements. With that in mind, Act 15/2010 defines the following lighting zones:

  • Dark places. This category comprises astronomical observatories, national or natural parks, and special protection areas, where lighting must be significantly reduced.
  • Low light zones. Suburbs, undevelopable land or rural areas. Lighting in these zones is only permitted on roads.
  • Medium light zones. Lighting is permitted on roads and pavements in urban residential or industrial areas.
  • High light zones. These include city centres, leisure centres and commercial facilities, as well as places with a large resident population and with a high level of tourism-related activities.

Exterior lighting should only be turned on in highly lit areas during established time slots, with consideration given to road management and safety. Decorative or commercial lighting systems should only be used between sunset and 23:00. This period can be extended to closing times, where applicable, or for a further hour on public holidays and on the eve of said holidays.

The law therefore stipulates certain pollution prevention measures, including proper lighting design and installation to reduce light pollution to a minimum and encourage energy savings and efficiency.



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