Associations of Positive and Negative Perceptions of Outdoor Artificial Light at Night with Nighttime Outdoor Behaviors and Health: Self-Reported Data Analyses on Urban and Suburban Residents in Japan

Nighttime light guarantees outdoor work, leisure, and other activities, and its convenience and security greatly improve the quality of human life. However, the negative effects of outdoor artificial light at night (ALAN) on humans are also being proven. This study aimed to examine the relationships between outdoor nighttime lighting and human behaviors (i.e., outdoor nighttime behaviors such as jogging and meeting friends) and health (i.e., physical and mental health, including sleep quality and stress) through how individuals feel about outdoor ALAN (i.e., ALAN perceptions) in their living environment. Two online questionnaire surveys were conducted among residents of Tokyo (Survey 1, N = 2000) and Tsukuba City (Survey 2, N = 500), Japan. Structural equation modeling results show that both positive and negative ALAN perceptions increase nighttime outdoor behavior in both surveys. In Survey 1, this association led to a deterioration in sleep quality and physical and mental health. The current findings contribute to understanding the controversial relationships between the pros and cons of nighttime light perceptions and behaviors and health. They also contribute to designing better nighttime lighting in outdoor public and private spaces with relevant restrictions by balancing the benefits and harms of outdoor ALAN.