Use shielded “full cut-off” lights to remove outwards lighting
Overall effectiveness category Awaiting assessment
Number of studies: 1
Background information and definitions
Artificial lighting disrupts the activity of nocturnal moths. Although some lighting is necessary for human activity and safety, conventional designs allow light to “spill” outwards from the direction in which the light is required, increasing pollution across a larger area. Changing the design of lights to reduce the amount of light which spills outwards (‘full cut-off’ lighting) may minimize the impact of lights on moths (Gaston et al. 2012).
Gaston K.J., Davies T.W., Bennie J., Hopkins J. (2012) Reducing the ecological consequences of night-time light pollution: options and developments. Journal of Applied Ecology, 49, 1256–1266.
Supporting evidence from individual studies
A replicated, paired, controlled study in 2011–2013 in 15 churches in Slovenia (Verovnik et al. 2015) found that lights with blinds to prevent light scattering, which were also colour-filtered, attracted fewer individuals and species of moths than conventional lighting. On church walls illuminated with yellow or blue light with blinds, both the abundance (12–20 individuals/year) and species richness of moths (10–15 species/year) were lower than on walls illuminated with conventional lighting and no blinds (abundance: 73 individuals/year; richness: 42 species/year). Fifteen churches in dark, rural areas were grouped into adjacent triplets, and illuminated in one of three ways: blue or yellow metal halide lamps, or the existing light (metal halide or sodium vapour, 70–400 W). Experimental lamps were 70 or 150 W, had custom-made filters to remove wavelengths shorter than 400 nm (blue) or 470 nm (yellow), and blinds to prevent the scattering of light away from the building. The illumination used on each church was rotated within each triplet each year. From May–September 2011–2013, moths were counted for 45 minutes six times/year within a 10 × 3 m area of wall on each church. Churches within a triplet were surveyed on the same night.Study and other actions tested