Artificial light at night: a neglected population health concern of the built environment.

Research inquiries of links between the built environment and population health have largely focused onphysical activity and social connectedness, associated health risks or benefits, and resultant chronic diseases; as well as access to healthy food, exposure to green views or green space, blue space, noise abatement, air pollution and biodiversity. Artificial light at night (ALAN) is mentioned as disturbing sleep but appears absent as a future challenge for urban design and health; indeed one ‘healthy by design’ brochure shows light as merely provision for pedestrians, and depicts a bright light as ecological and astronomical pollution. This Commentary draws the attention of the population health community to the health risks of ALAN from streetlights, lighted signage, and lit buildings. ALAN has increased exponentially since the adoption of public lighting ~130 years ago, with more than half the world’s population now living with a night sky brighter than a full moon.