Hey everyone, welcome back to my blog! Today, we’ll be exploring the different types of light pollution and the factors that contribute to it.
Light pollution refers to man-made light that is excessive, misdirected, and intrusive. An indicator of light pollution is the Night Sky Brightness (Hänel et al., 2018).
The four main types of light pollution include glare, light trespass, overlighting, and skyglow. Glare refers to excessive light that obstructs your vision, which might even lead to temporary vision loss; light trespass refers to light illuminating areas not intended and is unwanted; overlighting refers to when more light is produced due to clustering of light sources. Overlighting can also lead to sky glow, which is more specifically, the lit effect seen in overpopulated and urbanised areas.
Figure 1: Illustration of different types of light pollution (Project Terra, 2018)
The main driving factor for light and light pollution seems to be economic development. Many metropolitan cities like Hong Kong, New York, and Singapore, all fare badly on the Light Pollution scale. This is because metropolitan cities are typically characterised by modernised infrastructures such as neon billboards and illuminated skyscrapers. These structures stay lit – well into the night, as having an illuminated skyline indicates high productivity and is crucial for city branding and attractiveness (Law, 2021).
In Singapore, we also have a Night Lighting Master Plan devised by the Urban Redevelopment Authorities (URA) in 2006 in the Central Business District (CBD) area, ensuring that lights in the CBD stay on to form a distinctive part of Singapore’s nightscape. Areas key to our economic development, such as the Marina Bay district and the container terminals, are the more light-polluted areas in Singapore. Other drivers for light include safety (in keeping vehicular and pedestrian traffic on the roads safe) and security (in serving as deterrence against crime).
However, when the amount of lighting becomes excessive and unnecessary, light pollution occurs. In the next post, we will be exploring some of the implications of light pollution. See you then!
References
Falchi, F., Cinzano, P., Duriscoe, D., Kyba, C. C. M., Elvidge, C. D., Baugh, K., Portnov, B. A.,Rybnikova, N. A., & Furgoni, R. (2016). The new world atlas of artificial night sky brightness. Science Advances, 2(6), e1600377-e1600377. http://doi.org/10.1126/sciadv.1600377
Hänel, A., Posch, T., Ribas, S.J., Aubé, M., Duriscoe, D., Jechow, A., Kollath, Z., Lolkema, D.E., Moore, C., Schmidt, N., Spoelstra, H., Wuchterl, G. and Kyba, C.C.M. (2018). Measuring night sky brightness: methods and challenges. Journal of Quantitative Spectroscopy and Radiative Transfer, [online] 205, pp.278–290. Available at: https://www.sciencedirect.com/topics/physics-and-astronomy/night-sky-brightness
Law, M. (2021). Opinion: Melvyn Law on why light pollution poses a serious threat to urban cities aiming for sustainability. De51gn.
Project Terra. (2018). May Newsletter: Light pollution.
https://projectt3rra.weebly.com/blog/may-newsletter-light-pollution