By definition, light pollution is artificial lighting that is unnecessary, annoying or inefficient. Ron Chepesiuk stated in a January 2009 article in Environmental Health Perspectives that researchers consider nuisance lighting to be one of the fastest growing forms of environmental pollution, and it can have lasting effects on human health. While artificial lights are not inherently bad, their effects warrant mindful usage.
The Effects of Light Pollution on Health
1. Circadian rhythm disruptions: Different wavelengths of color affect the body differently. Several scientific studies found that lights with blue or white wavelengths have the ability to alter circadian rhythms, the body’s natural sleep cycle. In an August 2014 interview in Salon , author Paul Bogard explained that the human body evolved to associate blue wavelengths in light with waking up. When exposed to these wavelengths at night, some people may have a harder time falling asleep.
2. Disruptions in melatonin production: When a healthy individual falls asleep, tryptophan produces serotonin in the brain. The brain then converts serotonin into melatonin, a hormone that helps you fall asleep. The brain, however, requires darkness for it to convert serotonin into melatonin. When exposed to artificial white or blue lights, melatonin levels drop or the conversion of hormones is less likely to occur.
3. Accelerated tumor growth: Artificial lights do not cause cancer. According to Chepesiuk, exposure to artificial light at night may disrupt circadian rhythms and neuroendocrine physiology, which could lead to accelerated tumor growth. A December 2005 issue of Cancer Research discussed the increased breast cancer risks in female employees who work night shifts. Researchers collected blood samples from female volunteers exposed to different lighting conditions: natural daytime lighting, darkness at night, and artificial lighting at night. The results showed that tumors exposed to blood with higher melatonin levels (due to volunteers’ nighttime exposure to darkness) grew slower.
Similarly, a January 2008 issue of Chronobiology International discussed a study that found that Israeli women in neighborhoods that had outside artificial lights bright enough to read under at night had a 73 percent higher risk of developing breast cancer. Scientists also found that artificial light could affect the growth of prostate tumors and skin carcinoma incidences. While the evidence regarding the relationship of light pollution and cancer are inconclusive, the World Health Organization’s International Agency for Research on Cancer stated that shift work that disrupts circadian rhythms is “probably carcinogenic to humans.”
4. Development of sleep disorders: Circadian clock disruptions can lead to a variety of sleep disorders, including insomnia, shift-work sleep disorder and delayed sleep-phase syndrome. Sleep disorders and circadian rhythm disruptions are known to have various physiological effects on the brain and body, such as the development of depression or irregular heartbeats.
5. Exacerbation of pre-existing conditions: When light pollution comes in the form of flickering lights, the lights may exacerbate symptoms related to medical conditions, such as migraine headaches, epilepsy, solar urticaria or chronic actinic dermatitis. The two later conditions are rashes that develop because of exposure to the sun or artificial lights that emit ultraviolet radiation.
Artificial lighting has numerous benefits. For instance, it extends the length of days and provides safe illumination in homes and buildings. The technology is more hazardous when it becomes light pollution. Thankfully, bright light therapy solutions—such as light boxes and lamps that mimic natural lighting—can help you find a healthy way to realign your circadian rhythms at home and in the office. To benefit from the advantages of bright light therapy, browse Nature Bright’s selection of optimized lighting solutions.