Artificial nighttime lighting is rapidly changing worldwide with the widespread replacement of high-pressure sodium (HPS) streetlights by white light-emitting diodes (LEDs). While this transition aims to improve energy efficiency and enable smart lighting, it also alters the spectral composition and intensity of night skies, with potential ecological and social impacts.
In this study, we present ground-based measurements of nighttime brightness and spectral composition in multiple Negev desert settlements, using a portable photometer to compare areas illuminated by HPS versus LED streetlights. Our analysis reveals that LED-lit areas are not only brighter but also exhibit a shift in spectral composition towards shorter wavelengths, compared to the warmer, yellow HPS lighting. These findings highlight the spatial heterogeneity of light pollution in desert environments and underscore the importance of considering both brightness and spectral quality in evaluating the ecological and societal consequences of urban lighting changes.
