Light Pollution
How can it be too bright at night?
As more of the population moves into the cities, light from electrical sources often fill the night sky. Light pollution is defined as the inappropriate or excessive use of artificial light (1), such as lights from our buildings, streets and parking lots. Due to the lights a skyglow occurs, where light from many sources reflect off surfaces and travel upwards creating a ‘glow’ around the city (2). This prevents people to view the stars at night and it is also causing problems on the environment. Below is a snapshot of the Houston area light pollution map displaying different intensities by location.
What do we lose?
Nature and animal behaviors are disrupted since their biological clocks usually dictate when to sleep, hunt and travel. Excess use of light can also be a distraction to animals such as sea turtle hatchlings who are trying to make their way out to sea undetected. Migrating species of birds are attracted by the artificial night lights from buildings. Given that some of these birds migrate at night, light pollution often leads them astray and causes millions of deaths every year (1).
Human’s natural circadian rhythms are also affected by a decrease in the production of melatonin. Melatonin is a hormone that helps our bodies regulate sleep-wake cycles. Light directs the body to feel more awake which does not allow the body to rest and can cause ailments like sleeping disorders, headaches, worker fatigue, certain types of obesity to name a few (3).
How do we regulate light pollution?
Under normal nighttime conditions 2,500 stars are visible while only a few hundred are seen from a typical American suburb (3). Many states recognize the importance of reducing light pollution that they implement regulations into their zoning laws. Their goal is to provide ways to use light, while at the same time, conserving energy, providing public safety, preserving aesthetics, and promoting astronomical research (3).
What can you do today?
Some actions that we can take to immediately reduce light pollution, may include switching out incandescent light bulbs for lower temperature LEDs, using motion sensors or timers for outdoor lighting, and turning off devices an hour before bedtime. Technology is adapting by reducing blue-white lights in our phones, computers and TVs (1).
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Sources
(1) Our nights are getting brighter, and Earth is paying the price by Nadia Crake National Geographic www.nationalgeographic.com/science/2019/04/nights-are-getting-brighter-earth-paying-the-price-light-pollution-dark-skies/
(2) Understanding Light Pollution: Its Environmental Impact and Human Health Implications by Lamps Expo www.lampsexpo.com/blog/understanding-light-pollution-its-environmental-impact-and-human-health-implications/
(3) States Shut Out Light Pollution by National Conference of State Legislatures www.ncsl.org/research/environment-and-natural-resources/states-shut-out-light-pollution.aspx