Hong Kong: Pollution By Light!
Byline: Caitlin, Young Editor
Each year, our nights get brighter. In many places, star-studded skies have given way to a sky awash with artificial light.
In Hong Kong, a large city on the southeastern coast of China, residents are beginning to complain about lights--flashing signs and billboards that are kept on well into the night. And they're right -- Hong Kong is one of the most light-polluted cities in the world.
While the government recommends that lights be turned off from 11 pm and 7 am, not many businesses comply because it's not a law and there are no consequences. Citizens have tried taking matters into their own hands by campaigning for darker nights, but so far, it has only been mildly successful.
What Is Light Pollution?
Most light pollution comes from street lights, traffic lights, neon signs, shop fronts, and stadiums, but it can come from anywhere with excessive light. There are four kinds of light pollution -- sky glow, light trespass, glare, and clutter.
Light that is directed upwards or reflected from the ground into the sky is called skyglow. These particles of light, or photons, are scattered by dust in the air and often wash out the light coming from stars. Both man-made and natural light contribute to skyglow.
Light that is focused where it's not wanted, such as through a window, is known as light trespass. Glare refers to uncomfortably bright lights that often affects vision. It's most noticeable when driving at night, because overly bright streetlights are often shining in the wrong direction. Clutter is used to describe distracting and mismatched lights.
In cities around the world, governments have begun to manage light pollution. For example, many US states have dark sky legislation, which reduces skyglow and light trespass by requiring that streetlights only face downwards. Hopefully, Hong Kong's government is working on implementing changes as well for the best interest of their citizens.
Impact on the Environment
The impact of light pollution reaches far beyond just astronomy. Ecosystems around the world are altered.
The cycle of night and day are vital for many organisms. For example, aquatic life, which uses moonlight as a signal for reproduction season, is thrown off by artificial light. Lights lead baby sea turtles astray when they've just hatched and are searching for the reflection of moonlight to guide them to the ocean. The already decreasing number of pollinators (such as bees) have begun to dwindle as a result of artificial lights causing changes in plant growth and distracting the insects at night.
Humans are also affected. Light is known to disrupt and offset the circadian rhythm, or sleep-wake cycles, causing sleep disorders and other diseases. Glare can become a problem while driving, especially for older people.
Scientists are beginning to address light pollution and finding ways to minimize its effects. Either way, light pollution is as serious as air, sound, and water pollution, and needs to be managed for the well-being of our world.
Sources: Al Jazeera, CNN, darksky.org, globeatnight.org, Wikipedia
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|Title Annotation:||Our Earth|
|Date:||Feb 5, 2018|
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