Light pollution is not a widely recognized problem. Its negative impact on our lives is denied more often than air pollution or other effects of human activities. However, it is worth facing this topic, which we discuss with Katarzyna Szlachetko - an assistant professor in the Department of Administrative Law at the University of Gdansk and a legal advisor dealing with light pollution issues.
Katarzyna Szlachetko - PhD in legal sciences, assistant professor in the Department of Administrative Law at the Faculty of Law and Administration of the University of Gdansk; legal counselor. She specializes in administrative law, in particular local government law and the investment and construction process in the broadest sense. She serves on the Advisory Committee of the think tank Metropolitan Institute in Gdansk. She is a member of the International Academic Association on Planning, Law, and Property Rights and the International Dark-Sky Association. Since 2021, she has been carrying out the author's research program "Good Light Law" at the Metropolitan Institute, where she researches the legal and administrative conditions for developing and conducting sustainable outdoor lighting policies. In June 2022, the Metropolitan Institute Publishing House published, under her editorship, a Memorandum on Establishing the Legal Basis for Sustainable Outdoor Lighting Policy, which is the voice of experts on the environmental challenges and sustainability requirements for the planning and use of outdoor lighting infrastructure.
Wiktor Bochenek: Let's start with the basics - what is light pollution?
Katarzyna Szlachetko: Light pollution is a type of environmental pollution caused by uncontrolled, nuisance and harmful emissions of artificial light from outdoor and indoor lighting infrastructure devices, as well as from devices we use every day, such as TVs, laptops, tablets or smartphones.
This is not a new concept, although certainly not as familiar and established in the public consciousness as water, soil or air pollution. As a rule, we associate light with something positive, because it enables us to undertake various social and professional activities after nightfall, gives us a sense of security, increasing our comfort in moving around in the evening and at night. It also provides us with an aesthetic experience in the form of illumination of architectural objects or illumination of urban greenery. The role of lighting, especially outdoor lighting, cannot be overestimated. Outdoor lighting infrastructure can also become a part of creating the image of cities for tourism purposes.
Wiktor: When did attention to this problem begin?
Catherine: The problem of excessive light emission from outdoor equipment was first brought to the attention of astronomers as early as the 1970s. This is because it turned out that intense and uncontrolled emission causes light streams to "escape" into the sky, disrupting the contrast that is necessary for astronomical observations - both amateur and professional. Over time, scientific research has shown the negative effects of excessive light emission on living organisms and the environment, which contributed to the conceptual category of "light pollution." In the professional literature, one can also encounter the term "photo-pollution" or " light smog," but nowadays the most common term is precisely "light pollution" (from light pollution), possibly "artificial light pollution" to emphasize its anthropogenic origin.
Importantly, it is not a homogeneous phenomenon. It can take the form of "glare," i.e. excessive brightness, which causes visual discomfort and, when light sources are grouped together, constitutes a danger in traffic, blinding its participants. The accumulation of outdoor infrastructure devices in highly urbanized areas, especially those with high population densities, creates a glare effect hovering over inhabited areas, depriving residents of the opportunity to observe the dark sky.
Many people directly experience light pollution on a daily basis without even realizing it. This refers to street or neighborhood lights located in front of our apartment windows, or light coming from a neighboring property, which "falls" after dusk through our bedroom windows, disturbing our night's rest.
The U.S.-basedInternational Dark-Sky Association defines light pollution as "inappropriate or excessive use of artificial light" that "can have serious environmental consequences for people, wildlife and our climate."
Victor: Is light pollution harmful to us?
Catherine: Yes, light pollution is harmful to humans, as well as to animals and plants. I am not an expert in medicine, biology or ecology, so in my research on the optimal model for a sustainable outdoor lighting policy, I rely on scientific sources and data presented by experts. And these show unequivocally that overexposure of living organisms to artificial light negatively affects the so-called circadian rhythm, which regulates all physiological processes (on the principle of the "biological clock"). Without going into detailed considerations in this regard, because I am not an expert, the point is that living organisms need a daytime regime with natural light and a nighttime regime with natural darkness in order to function properly. Nighttime is the time for sleep, or rest and recuperation.
light pollution
Photo: Dmitry Brant | © Wikimedia Commons CC BY-SA 4.0
"Presence" of artificial light disrupts this regime by interfering with melatonin production. Instead of "quieting" the body, it causes it to "activate". Each of us can conduct an experiment. When we feel sleepy and basically ready to go to bed, but are still using our computers, phones or watching TV "for a while," we find that we suddenly have trouble falling asleep. It is the disruption of the circadian rhythm by erroneous signals caused by light pollution. The same may be true of the "intrusion" of streetlight into our apartment. The abnormal expression of hormones causes insomnia, chronic fatigue and even depression.
What's more, scientists say that light pollution may co-facilitate or promote the development of some autoimmune diseases, and is even a likely carcinogen. An increased risk of breast cancer and prostate cancer is indicated. The same is true for some animal and plant species. Overexposure to light from outdoor infrastructure disrupts their chronobiological processes. Many nocturnal and migratory species of birds, fish, turtles, insects, carnivores need darkness for normal existence, and for some plants darkness is necessary to carry out so-called photoperiodism. Uncontrolled and oppressive light emissions lead to shrinking populations of animal species and changing flowering patterns of plants, thus threatening biodiversity, which is of fundamental importance to the natural world and human existence. There is also increasing talk about the impact of light pollution on climate change. Excessive heat release from extensive and uncontrolled outdoor lighting infrastructure can amplify the greenhouse effect.
