Origins and Ecological Relevance of International Obtrusive Light Thresholds

Light pollution from outdoor lighting impacts astronomical observations, ecology, and human health, with its global increase threatening previously dark environments. This paper examines international obtrusive light thresholds, revealing that current standards are primarily human-centric and based on outdated light sources. Environmental lighting zones, initially designed for inhabited areas, lack the scope to safeguard sensitive ecosystems. Analysis shows that current zones and thresholds need restructuring to include ecological considerations, particularly for conservation areas where species can be affected by very low light levels. Standards need updating to integrate ecological thresholds for effective environmental protection.