A holistic evaluation of an efficient and environmentally-sound public lighting system to control biological colonisation on architectural heritage

Abstract

Ornamental lighting plans are governed by aesthetic considerations, energy efficiency, and recommendations regarding their environmental impact; however, they do not account for their potential effect on the biological colonisation present stone-built heritage. Artificial light can promote the development of phototrophic colonization, in the form of SABs composed of algae and cyanobacteria, if emitted at wavelengths that stimulate photosynthesis. The implementation of innovative lighting solutions must comply with the strict regulatory framework within the urban fabric, resembling white light due to the impossibility of using monochromatic lighting on a permanent basis. It has been hypothesised that the combination of narrow-band amber and green LED light, with a primary peak at 593 nm and a secondary peak at 528 nm, will have a biostatic effect by illuminating between the main absorption peaks of photosynthetic pigments while maintaining and adequate white-like appearance.