Flora and fauna face challenges from artificial light during the night, and stars are no longer visible in various regions of the night sky. Emlyn Etienne Goronczy, a lighting designer at Studio DL, a successful European planning office with branches in Hanover, Stuttgart, Amsterdam and Warsaw, specializes in preventing light pollution. He shared his expertise with us during a presentation at the TRILUX Academy, among other occasions. For those who missed the event, we asked for further insights.

Why is it important to consider light pollution in lighting design?

Light pollution is an important social issue today. For example, it can affect human health, by disrupting the natural biorhythm. However, people can determine the light dose themselves and thus protect themselves to a certain extent from too much light. In addition, evening activities such as watching TV or playing sports influence people's biorhythms more than outdoor lighting.

Emlyn Etienne Goronczy, Lighting Designer

In contrast to us, animals find it difficult to escape the light at night. Many species depend on natural darkness, whether for orientation (in the starry sky), foraging or reproduction. Artificial light can disrupt these activities and ultimately lead to a decline in the respective populations. This makes the impact of poorly planned lighting at night even more dramatic. Accordingly, outdoor lighting designers have a special responsibility.

So, the drivers are mainly ecological?

No, not at all. There are also strong economic incentives. Around 120 terawatt hours are consumed annually in the USA for outdoor lighting. About half of this could be saved with better light planning and control. This corresponds to potential savings of approximately 21 million tons of CO2 or 3.3 billion dollars per year, which could be invested elsewhere. This is similar in German cities and municipalities but of course on a different scale.

Are there any types of luminaires that you recommend for protecting the night sky?

This cannot be answered in general terms but only on a project-specific basis. A country road without façades on the sides lacks vertical absorption surfaces. In this case, the right solution may be a Full Cut Off luminaire (ULOR 0 luminaires) that provides precisely directed light exclusively onto the roadway. This would again be the wrong approach for an urban environment where vertical illuminance levels are also required for facial recognition (for a sense of safety, quality of stay, etc.).

Basically, I think it is important to keep illuminance levels as low as possible and to have controllable and dimmable luminaires. In this sense, lighting management is a key component in achieving Dark Sky goals.

In your opinion, what is the ideal balance between safety through lighting and protecting the night sky?

Here, too, there is no universal blueprint. Good lighting is always planned on a site-specific and interdisciplinary basis. The area-specific project requirements are defined at the beginning. These include the needs of society, such as the feeling of safety and the quality of stay, as well as the needs of the ecosystem. This is followed by an interdisciplinary analysis of the site by architects, urban planners, biologists and lighting designers. They weigh up the various needs and balance them on a project-specific basis. The result is, therefore, always a compromise.

The refurbishment of municipal outdoor lighting is urgent. What should cities and municipalities look out for?

The most important thing is not to panic or take action. Those responsible for the project should seek professional advice as a first step. A planning team consisting of a lighting designer, a biologist and a luminaire manufacturer is recommended. Together they can select or develop product solutions that meet the requirements of the project. Blanket solutions or recommendations should be viewed with caution and may do more harm than good.

Thank you very much for the interview!

TRILUX practical example

Sonnenbrunnen urban quarter with a dark sky

The city of Heilbronn was looking for a customized outdoor lighting solution for the Sonnenbrunnen district in order to reduce energy costs and, at the same time, increase the quality of light and thus, the quality of stay. The lighting requirements were extremely varied - tailor-made light was required for streets and crosswalks as well as for squares, footpaths and a park. An important contribution to a clear view of the stars: only luminaires that emit no or only a very low luminous flux upwards are used, e.g. our Lumega IQ 70 and Viatana mounted luminaires.

For optimum visual conditions, the lighting technology of each light point has been perfectly adapted to the individual area of application.