You've heard of air, noise and water pollution numerous times but light pollution is less known. This type of pollution which is defined as poorly installed light using inefficient lighting or excessive lighting, not only masks views of the night sky but also causes many environmental problems and skyglow which is the brightness of the night sky usually seen in large cities as a result of light pollution. It can disrupt wildlife and ecosystems that rely on day and night cycles for activities like reproduction, nourishment, sleep and protection from predators. Moreover, light pollution suppresses melatonin production which is necessary for the health of humans. The challenge is maintaining the required lighting in buildings while reducing environmental and human health implications.
Limiting Light Usage
The International Dark-Sky Association (IDA), a non-profit organization working to help stop light pollution, estimates that 30 percent of outdoor lighting in the United States is wasted, amounting to 21 million tons of carbon dioxide emissions a year. The IDA recommends the use of lights that point downward, preferably at a 90-degree angle, rather than up into the sky and only using light where it is needed. Lights should also only be as bright as necessary and shut off or dim after business hours. Too much light, which also includes unwanted light that shines on another property or light trespass can actually be unsafe as they can be blinding.
Types of Light
Low-pressure sodium (LPS) light which emits a yellow light, and high-pressure sodium (HPS) lights which emit an orange-colored light are among the most efficient electrical light source, mainly used for street lights and security lighting. Metal halide and light emitting diodes (LED) are small light bulbs that produce a white light and consume less energy and have a longer lifetime. LED lights are dimmable to lower illumination making them a great choice in areas where full brightness is not always needed, thereby saving energy and reducing light pollution at night.
Types of Fixtures
Fully shielded and full cut-off outdoor light fixtures minimize glare and energy waste. They do not emit light above a 90 degree angle and allow for better vision at night. These light fixtures are available for residential and commercial buildings and include wall mount fixtures, barn lights, walkway bollards, decorative fixtures, properly-aimed PAR floodlights, flush mounted or side shielded under canopy fixtures and streetlights. When possible, use timers, dimmers, and motions sensors.
Blue light which is harmful to human health and the ecology brightens the night sky more than any other color of light. To minimize blue light, light trespass and skyglow, the IDA recommends using "dark sky friendly" light fixtures. This means using lighting that is fully shielded and has a "warm" color temperature of 3000 Kelvins or lower.
Do you believe that light pollution is a problem? What are some other ways to minimize light pollution? Share your thoughts below.