To reduce the impacts of light pollution on individuals, society, and on the environment, light pollution needs to be targeted from an overproduced/overconsumed, efficiency, and from an externality standpoint.
Overproduction and overconsumption of light come hand in hand, referring to when more light than necessary is produced or consumed. This issue could be mitigated with the implementation of Light Management Zones (LMZ), by demarcating areas based on their geographical location, proximity to nature and residential areas, and the nature of the dominant activity in the area. A specific quota is then imposed on the maximum light permissible, where the quota is tweaked for each zone.
Areas in close proximity to nature should be classified as high priority zones, due to the impact of light on biodiversity and the lack of the need for light in these areas. The amount of permissible light in this zone should hence be minimal. Residential zones should be given moderate priority, with temporal light management in the zones (i.e limits on the amount of light allowed after certain hours) to reduce the impact of light on residents without compromising the safety at these areas. Lastly, for commercial and industrial areas where the demand and the need for light are higher, more light could be permitted. The light management efforts in commercial and industrial efforts could be focused on effective lighting fixtures instead.
A case in point would be South Korea, where LMZs have been implemented. The city area has been segmented into four zones, based on their extent of lighting needs and the impact of light in these areas.
Figure 1: LMZ classification in Korea (Lim et al., 2018)
For each zone, specific limits were set on advertisement and decorative lighting, which were found to be significant contributors to light pollution in Seoul (Ngarambe & Kim, 2018). LZ1 had the lowest permissible light luminance permitted, whereas LZ4 had higher permissible limits.
Figure 2: Maximum luminance allowed for each LZ (Ngarambe and Kim, 2018)
Similar intervention methods could hence be implemented globally, especially in urbanised countries and cities where illuminated infrastructures are a common sight. Although, there have been insufficient follow-up studies to determine the effectiveness of these LMZs in Korea and more research and studies should be done.
References
Lim, H., Ngarambe, J., Kim, J. and Kim, G. (2018). The Reality of Light Pollution: A Field Survey for the Determination of Lighting Environmental Management Zones in South Korea. Sustainability, 10(2), p.374.
Ngarambe, J. and Kim, G. (2018). Sustainable Lighting Policies: The Contribution of Advertisement and Decorative Lighting to Local Light Pollution in Seoul, South Korea. Sustainability, [online] 10(4), p.1007. Available at: https://www.mdpi.com/2071-1050/10/4/1007