The Role of Urban Lighting in Sustainability

The role which outdoor lighting plays in our modern 24/7-world cannot be underestimated. To the date, there are plenty of research articles and review papers, revealing and emphasising various impacts of an artificially lit urban environment on three overarching themes: human beings, environmental sustainability and city aspects.

To be more precise, light through visual and non-visual mechanisms (as well as through a third class of mechanisms, which appear when light exposure falls on skin) effects on psychological and physiological functioning of human beings. Environmental effects are predominantly linked with light pollution, involving issues of sky glow, as well as lighting impacts on flora and fauna. Moreover, taking into account that lighting comprise 16% of the world’s electricity consumption, energy efficiency is becoming one of the essential considerations when planning lighting design projects. Finally, the impacts of different layers (i.e. functional lighting, creative lighting, holiday lighting) of outdoor lighting on city image, identity, holistic perception of the city and its important places (e.g. hierarchy within architectural ensembles, appearance of architectural dominants), entertainment and playfulness after dark are also recognized within the lighting professional community.

The Sustainable Development Goals (SDGs) aim at providing a healthier planet for present and future generations. At the most recent SDG summit held in 2019, Member States recognized that the achievements accomplished to date have been insufficient to achieve this mission. Our recent paper (, contributors: P. Tavares, P. Bhusal, P. Pinho, D. Ingi – Lighting Research Group, Aalto University and L. Araújo – Federal University of Juiz de Fora) presents a comprehensive literature review of 227 documents contextualising outdoor lighting with SDGs, showing its potential to resolve some existing issues related to the SDG targets. From a list of 17 goals, six SDGs were identified to have relevant synergies with outdoor lighting in smart cities, including SDG 3 (Good health and well-being), SDG 11 (Sustainable cities and communities), SDG 14 (Life below water) and SDG 15 (Life on land). This review also links efficient lighting roles partially with SDG 7 (Affordable and clean energy) and SDG 13 (Climate action) through Target 7.3 and Target 13.2, respectively. This paper identifies outdoor lighting as a vector directly impacting 16 of the 50 targets in the six SDGs involved. Each section in this review discusses the main aspects of outdoor lighting by a human-centric, energy efficiency and environmental impacts. Each aspect addresses the most recent studies contributing to lighting solutions in the literature, helping us to understand the positive and negative impacts of artificial lighting on living beings. In addition, the work summarises the proposed solutions and results tackling specific topics impacting SDG demands.

Overall, outdoor lighting was revealed as a powerful tool to support Sustainable Development Goals. With its professional, evidence-based design, the potential for a positive impact on various aspects of human life, as well as on the quality of the environment and energy efficiency levels is promising. It is worth noting that the same outdoor spaces can hypothetically require simultaneously competing settings for supporting energy efficiency, environmental sustainability, light pollution and citizens’ comfort. Nevertheless, the development and integration of smart lighting systems, which allow the creation of dynamic, adaptive and intelligent lighting scenarios, may solve this problem. Such lighting systems provide the opportunity to establish a reasonable balance between the lighting needs of human beings and environmental sustainability and energy efficiency. Undoubtedly, such a balance must be considered as a global urban planning issue.