Optimizing exterior lighting illuminance and spectrum for human, environmental, and economic factors.

Abstract

With the recent widespread adoption of LED lighting in outdoor areas, numerous concerns have been raised about the potential for harmful effects on humans, animals, plants, and the night sky. These stem from the high blue light content of some LED bulbs and an incentive to increase lighting levels caused by higher efficiency and lower costs. While new lighting installations are often described as environmentally friendly due to their energy efficiency, factors such as light pollution are often neglected or not given enough weight. This research focuses on optimizing the design of exterior lighting for human, environmental, and economic factors using a multi-criteria decision analysis. Based on data in the literature and survey research, illuminance and spectrum alternatives were scored relative to each other using the analytic hierarchy process and multi-attribute utility theory. The findings of this study support the use of artificial illumination at levels similar to a full moon (0.01 fc) and a warm white spectrum (2700K or 2200K), with amber LED becoming a better choice if its energy efficiency and cost effectiveness improve in the future. This methodology can be used in the future as a framework for lighting design optimization in different settings.