Artificial Light at Night (ALAN)

In response to the widely shared news articles where scientists believe artificial light may be affecting the natural ecology of plant life by creating extended photosynthesis, the ILP Technical Committee has been discussing the findings.

The ILP provided written and verbal evidence at the House of Lords Science & Technology Committee inquiry into the effects of artificial light on human health in 2023. During the inquiry, the ILP welcomed and supported any research and investigation into the application of light & lighting that leads to an improved understanding and supports / develops good lighting practice. We acknowledged that artificial light at night (ALAN) brings many benefits to users such as the comfort and safety of people and that a balanced approach needs to be taken to consider both the needs of humans and ecology.

The ILP Guidance notes GN01 The reduction of obtrusive light and GN08 Bats and artificial lighting provide good practice in relation to reducing the impact of ALAN on the environment. The ILP also aligned to the responsible Outdoor Lighting at night (ROLAN) manifesto which also aims to reduce the impact on the environment at night.

As the impact and understanding of ALAN on the environment is a rapidly evolving field, the ILP will be regularly reviewing all new academic research to ensure the members are provided with the most appropriate advice at the time. Furthermore, it is important to note that ALAN is not caused by just street lighting alone and that all research papers should clearly identify sources of ALAN in the study to ensure accurate messages such as the impact of different light sources & responsibility of those owners or maintainers can be clearly defined.

As lighting practitioners it is our responsibility to adopt best practices to limit the use of uncontrolled lighting be it domestic & interior lighting, all exterior lighting i.e. façade & lit buildings, security lighting, or illuminated advertising signs, etc. that could be inadvertently contributing to ALAN. The ILP recommends the adoption of best practices including the ROLAN manifesto which the ILP amongst other organisations partners to support the application of the five principles of ROLAN.

Stuart Morton, ILP Technical Committee