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Effects on animal and human health and psychology

Effects on animal and human health and psychology Main article: Over-illumination Main article: Ecological light pollution Light pollution in the skiing resort Kastelruth in South Tyrol. Medical research on the effects of excessive light on the human body suggests that a variety of adverse health effects may be caused by light pollution or excessive light exposure, and some lighting design textbooks[28] use human health as an explicit criterion for proper interior lighting. Health effects of over-illumination or improper spectral composition of light may include: increased headache incidence, worker fatigue, medically defined stress, decrease in sexual function and increase in anxiety.[29][30][31][32] Likewise, animal models have been studied demonstrating unavoidable light to produce adverse effect on mood and anxiety.[33] For those who need to be awake at night, light at night also has an acute effect on alertness and mood.[34] In 2007, "shift work that involves circadian disruption" was listed as a probable carcinogen by the World Health Organization's International Agency for Research on Cancer. (IARC Press release No. 180).[35][36] Multiple studies have documented a correlation between night shift work and the increased incidence of breast and prostate cancer.[37][38][39][40][41][42] A more recent discussion (2009), written by Professor Steven Lockley, Harvard Medical School, can be found in the CfDS handbook "Blinded by the Light?".[43] Chapter 4, "Human health implications of light pollution" states that "... light intrusion, even if dim, is likely to have measurable effects on sleep disruption and melatonin suppression. Even if these effects are relatively small from night to night, continuous chronic circadian, sleep and hormonal disruption may have longer-term health risks". The New York Academy of Sciences hosted a meeting in 2009 on Circadian Disruption and Cancer.[44] Forty Danish female shift workers in 2009 were awarded compensation for breast cancer "caused" by shift work made possible by light at night – the most common cause of light pollution.[citation needed] Red light suppresses melatonin the least.[45] In June 2009, the American Medical Association developed a policy in support of control of light pollution. News about the decision emphasized glare as a public health hazard leading to unsafe driving conditions. Especially in the elderly, glare produces loss of contrast, obscuring night vision