Abstract: A shift towards more energy-efficient light sources for outdoor lighting such as light-emitting diodes (LEDs) is underway. Photometric measures are not sufficient to capture how users experience the light, so complementary tools are required. This study aimed to develop an observer-based environmental assessment tool, based on bipolar semantic differentials, for outdoor lighting in urban spaces. Exploratory (N = 130) and confirmatory (N = 117) factor analyses of observations of lighting installations made by laypersons on-site along pedestrian paths, resulted in two dimensions of high reliability: the Perceived Strength Quality (PSQ, Cronbach's alpha = 0.82–0.85) and the Perceived Comfort Quality (PCQ, Cronbach's alpha = 0.77–0.81). PSQ and PCQ differentiated between light sources of different illuminance level, colour temperature and colour rendering. Regression analyses showed that the perceived lighting qualities helped to explain the variance in visual accessibility, whereas PCQ helped to explain perceived danger in the environment. The perceived lighting qualities can add to the understanding of pedestrians' perception of outdoor lighting, and is proposed as a complementary tool for development of sustainable light designs in the urban environment.

Abstract: Improvements in the luminous efficiency of outdoor lamps might not result in energy savings or reductions in greenhouse gas emissions. The reason for this is a rebound effect: when light becomes cheaper, many users will increase illumination, and some previously unlit areas may become lit. We present three policy recommendations that work together to guarantee major energy reductions in street lighting systems. First, taking advantage of new technologies to use light only when and where it is needed. Second, defining maximum permitted illuminances for roadway lighting. Third, defining street lighting system efficiency in terms of kilowatt hours per kilometer per year. Adoption of these policies would not only save energy, but would greatly reduce the amount of light pollution produced by cities. The goal of lighting policy should be to provide the light needed for any given task while minimizing both the energy use and negative environmental side effects of the light.

Abstract: Recognition of the extent and magnitude of night-time light pollution impacts on natural ecosystems is increasing, with pervasive effects observed in both nocturnal and diurnal species. Municipal and industrial lighting is on the cusp of a step change where energy-efficient lighting technology is driving a shift from “yellow” high-pressure sodium vapor lamps (HPS) to new “white” light-emitting diodes (LEDs). We hypothesized that white LEDs would be more attractive and thus have greater ecological impacts than HPS due to the peak UV-green-blue visual sensitivity of nocturnal invertebrates. Our results support this hypothesis; on average LED light traps captured 48% more insects than were captured with light traps fitted with HPS lamps, and this effect was dependent on air temperature (significant light × air temperature interaction). We found no evidence that manipulating the color temperature of white LEDs would minimize the ecological impacts of the adoption of white LED lights. As such, large-scale adoption of energy-efficient white LED lighting for municipal and industrial use may exacerbate ecological impacts and potentially amplify phytosanitary pest infestations. Our findings highlight the urgent need for collaborative research between ecologists and electrical engineers to ensure that future developments in LED technology minimize their potential ecological effects.