Hello everyone! Welcome back to our blog. As we finished radiation pollution, we thought it would not make sense to talk about light pollution, another part of the electromagnetic spectrum. As we talked about in our introduction post to radiation pollution, visible light is the only part of the electromagnetic spectrum that an average individual can see (Hadhazy, 2015). While radiation pollution may be harder to grasp, light pollution has been plaguing our environment ever since the invention of artificial lighting (Narisada & Schreuder, 2004).
In our next few posts, we will be discussing light pollution and the Czech Act on Protection of the Air, which is the only legislation that we came across pertaining to controlling light pollution. Let’s begin!
Why should we celebrate pollution?
As noted by Narisada and Schreuder (2004), light is necessary for all life on earth, but the issue of light pollution looks at the negative side-effects of artificial lighting. Yet, the negative side-effects of artificial lighting are celebrated as a proxy of ‘development’ by measuring ‘skyglow’. This confusing reality was pointed out by Professor Taylor, which also baffled us when we relooked at the definition of “pollution”. If the definition of pollution is “Any substances … that degrade the natural quality of the environment … usually impaired by the presence of pollutants and contaminants” (EPA, n.d.), why should the negative effects of excess light be celebrated? Although the EPA may deem that light is not a “substance”, we should not forget that the natural quality of the environment is degraded as a result of light pollution.
Types of light pollution
Artificial Light at Night (ALAN), is the term coined to represent the ubiquity of using artificial lighting to light up the dark nights. While light is useful in most cases, the issue of light pollution arises when light affects the environment and humans. We would also like to point out that light pollution is the result of wasteful use of electricity, where the benefit and uses of light is outweighed by the amount wasted. Thus, light pollution occurs when artificial lighting wastes resources instead of being used beneficially (Narisada & Schreuder, 2004). This can be best illustrated when we look at the different types of light pollution, whereby the three commonly recognized forms of light pollution are skyglow, spill light/light trespass and glare.
Firstly, skyglow is the type of light that is directed skywards and then scattered back to the surface (Narisada & Schreuder, 2004). Skyglow can either be a result of improper design causing leakages skyward or due to reflection of light by other materials. Skyglow mainly occurs due to the inefficiency of lighting for useful purposes (Narisada & Schreuder, 2004). In comparison, when lighting is directed skywards for decorative purposes, this is not light pollution as the function of these lighting is fulfilled (i.e. for aesthetic purposes). This distinction is important when considering what is light pollution and what is not. We believe this could also be the reason why ‘skyglow’ is a proxy of ‘development’, as a country’s level of development is tied to the amount of resources that can be used for decorative attractions. Being able to use light decoratively would mean that the basic necessities of a country are met while being able to spare additional resource to be attractive, signifying higher levels of affluence.
Secondly, spill light or light trespass is the result of light being “spilled” or “trespassed” into areas that are out of what it was designed for. While artificial lighting is used functionally and generally directed, light scattering occurs due to the presence of air particles. This process of light scattering is also known as “Rayleigh scattering”, whereby light is scattered by refraction of air particles (Young, 1981). In this case, the term “scattering” is loosely used but illustrates how air particles causes light pollution by causing useful light to be “spilled” into regions that the artificial lighting was not designed for or “trespassed” into areas that were not supposed to be lit. Unlike skyglow, which is caused by reflection of surface materials such as roads, spill light/light trespass occurs as a result of air particles. Thus, air pollution further exacerbates the issue of light pollution as more particles in the air would mean greater levels of spilled light (Garstang, 1991).
Lastly, glare occurs due to excess light causing discomfort (Narisada & Schreuder, 2004). This occurs when the lighting is not properly adjusted for use, most notably when using bright screens to work in low-light conditions. Improper designs can cause glare as the light is directed too strongly onto a subject. While discomfort arises for users using excessively bright screens, glare can also cause accidents on roads, also known as disability glare (Narisada & Schreuder, 2004). To briefly compare, both types of glares causes discomfort, but disability care renders individuals unable to function properly as the physiologic function of the eye is impaired (Narisada & Schreuder, 2004). This is best illustrated when comparing how you would shade your eyes due to a sudden change in lighting conditions (e.g. suddenly turning on your lights in a dark room) to the pain in your eyes when focusing on your screen for a prolonged time. While disability glare is a reflexive action, discomfort glare is a response to eye strain.
Lights out!
In this post, we expanded and discussed the types of light pollution in detail while critiquing the use of ‘skyglow’ as a proxy to measure ‘development’. To learn more about light pollution in detail, do check out Jean and Trudie (our fellow course mates) blog where they dedicate it to the topic of light pollution! We would also like to credit our title to their blog, aptly named: toobrightinhere. In our next post, we will look at the effects of light pollution on human health and our environment before proceeding into the Czech Act on Protection of the Air. For now, lights out!
Ryan
References
Bakr, A. F., Diab, I., & Saadallah, D. (2007). Detecting Inefficient Lighting Solutions: Step-by-Step Geographic information system (GIS) Technique.
EPA. (n.d., 2020). Environmental Issues Terms & Acronyms. Retrieved from https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do;jsessionid=A7jqOelu4zV1TkXNKeZyriwhgkqhpQxWCEuyjy2NF1_3r-MGMhFn!1911837198?details=&vocabName=Environmental%20Issues%20Glossary&filterTerm=pollution&checkedAcronym=false&checkedTerm=false&hasDefinitions=false&filterTerm=pollution&filterMatchCriteria=Contains
Garstang, R. (1991). Dust and light pollution. Publications of the Astronomical Society of the Pacific, 103(668), 1109.
Hadhazy, A. (2015). What are the limits of human vision? Biology. Retrieved from https://www.bbc.com/future/article/20150727-what-are-the-limits-of-human-vision
Narisada, K., & Schreuder, D. (2004). Light pollution handbook. Springer.
Young, A. T. (1981). Rayleigh scattering. Applied optics, 20(4), 533-535.