Contents I. Introduction
Many hotel guests rely heavily on artificial lighting provided by room lamps, resulting in limited utilization of natural light. Unfortunately, this habit leads to prolonged closure of curtains, rendering rooms dark even during daylight hours. Recent research conducted at the University of Oregon revealed that darkened rooms harbor significantly higher levels of actively reproducing living bacteria, accounting for 12 percent, compared to rooms exposed to daylight (6.8 percent) or UV light (6.1 percent) [1]. Hence, keeping curtains closed for extended periods poses health risks [2].
