Light Pollution???
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On a recent car commute, I heard a radio discussion on the topic of “light” pollution. At first I thought they were talking about people who monitored their pollution, but of course they meant the illumination type of light. It turns out there are many people concerned with how city lighting and personal lighting affect the environment. The most obvious of those people are astronomers since it is more difficult to see stars and planets in a more lighted nighttime environment. Of course, there are others too, and the effects are more wide reaching than I thought. But we need those lights for safety, right? Maybe. Wikipedia states, “it is generally agreed that many people require light to feel safe at night, but campaigners for the reduction of light pollution often claim that badly or inappropriately installed lighting can lead to a reduction in safety if measured objectively, and that at the very least, it is wrong to assume that simply increasing light at night will lead to improved safety.” The safety issue aside, it is good to consider the impacts and how to effectively use light. Not only are there impacts on energy efficiency, but there are also environmental and human health impacts.
Some of the things we can do to control light pollution in the energy efficiency areas include:
- Directing the lighting only where it is needed to optimize the amount used
- Installing dimmable lights to use only the necessary amount of illumination
- Using energy efficient bulbs, including LED and fluorescent types
- Implementing solar lighting where possible
- Using sensors that turn lights on only when they are needed. Motion and darkness detectors widely available.
One city, Oakland, CA, has installed LED streetlights and saved money while greatly reducing light pollution. Plus LED’s have the ability to be easily dimmed and respond to motion detection. What a great thing to do on a citywide basis!
The environmental impacts include the ability to see the night sky, but also there are examples where light pollution affects the direct mortality in species of birds, turtles and insects. Light pollution also interferes with the reproduction in corals and fireflies and with predation in a variety of species. It doesn’t stop there either; there are more.
So if light pollution affects animals, it probably affects humans too. In fact, there are some studies that show that artificial light exposure at night can be linked to an increased cancer risk. Apparently light suppresses melatonin and melatonin suppresses cancer growth. A reduction in melatonin then leads to an increased cancer risk. Other health impacts include loss in visual acuity, hypertension, increased anxiety, and headaches. Of course when there is unwanted light or “light trespassing”, it can cause disruption in sleep, and a reduction in sleep has many health impacts.
This just scratches the surface of the light pollution issue. Wikipedia is one place where you can learn more. It is an interesting topic, and I know I am going to put more thought into it. What are your thoughts and suggestions on this topic?
Don’t be so quick to dismiss the safety issue: a lot of light pollution is due to glare from lamps that are too bright, or directed outward, in the name of safety; yet these very strategies are counterproductive and actually decrease our safety. A bright path within an otherwise dark landscape offers would-be attackers both hiding places and well-lit targets. And as I’ve written on my site, nobody enjoys looking into the halo of a 75w bulb, so we look away… and don’t see the fellow in the black ski mask jimmying the lock on the door next to that light.
The International Dark-Sky Association is the predominant group organizing efforts to reduce light pollution. Their site is a wealth of information, including “IDA-Approved” fixtures that minimize glare. Reducing the amount of light we use is only half the battle; we also need to direct the light we do use more judiciously.