Other than varying the colour temperature of light based on the location and setting, the type of light fixture used and additional technologies incorporated also affects how pollutive the source is.
How does the design of the lighting used matter, you may wonder? Every year, an estimated 30% of outdoor lighting in the United States is generated as excess lighting (Gallaway et al., 2010) due to unshielded or poorly designed lighting fixtures, amounting to an annual expenditure of $3 billion. Cutting down on unnecessary production of light is hence a win-win situation, reducing the cost of electricity bills and at the same time reducing the harmful impacts of light pollution on individuals and on the environment.
An ideal light fixture is one that allows no light to be emitted upward – i.e Upward Lighting Ratio of 0%. This is achieved through the full cut-off fixture and the fully-shielded fixtures seen in figure 1 below.
Figure 1: Types of light fixtures and how they affect the emitting of light
The full cut-off and fully-shielded fixtures prevents unnecessary light from being emitted into the sky, reducing the wastage of energy. Non-shielded fixtures and upright light poles are also inefficient since the light emitted is not shone on the intended areas.
Other than light fixtures, other technological aids such as motion-sensored lighting and timers can also help to reduce the production of unnecessary light. Motion-sensored lighting used in commercial buildings allows light to be produced only where there is human traffic, whereas timers turn off light sources after a certain time. These applications could be incorporated into office buildings and commercial buildings near heavily light-polluted areas in the city, such as in the CBD area in Singapore, to prevent lights from being turned on throughout the night.
Bearing these factors in mind, we will be exploring how to adapt these criteria into policies in our next post, to ensure that light produced is efficient and adequate.
References:
Gallaway, T., Olsen, R. N., & Mitchell, M. D. (2010). The economics of global light pollution. Ecological Economics, 69(3), 658-665. https://doi.org/10.1016/j.ecolecon.2009.10.003
Global Designing Cities Initiative. (n.d.). Lighting Design Guidance. https://globaldesigningcities.org/publication/global-street-design-guide/utilities-and-infrast ructure/lighting-and-technology/lighting-design-guidance/
VOLT Lighting. (2020). VOLT® Lighting. [online] Available at: https://www.voltlighting.com/learn/using-dark-sky-approved-lighting-to-reduce-light-pollution