隨著經濟的快速發展，光汙染問題日益凸顯，已成為全球不可忽視的汙染之一。人工照明不僅對人類自身健康造成嚴重危害，更對生物多樣性和生態系產生深遠影響。
來源：NASA https://earthobservatory.nasa.gov/images/90008/night-light-maps-open-up-new-applications
光汙染會直接幹擾自然光-暗迴圈，破壞生物體的晝夜節律光夾帶[1]，造成生物鐘紊亂，導致相關疾病正在且不斷威脅人類健康[2]。全世界超過80%的人口受到不同形式的光汙染的影響[3]。光汙染對人類健康的潛在影響不僅會造成睡眠障礙[4]，還會引起更多疾病，如肥胖[5]~[7]、代謝紊亂[8]、精神障礙[9][10]，甚至癌癥[11]~[14]等。其中，值得註意的是，涉及癌癥的幾個關鍵過程都受晝夜節律的控制[15]。可見，晝夜節律與人類的身體健康狀況息息相關。另外，有研究表明，戶外人造光源中的藍光光譜暴露與結直腸癌[16]、前列腺癌和乳癌[17]密切相關，而可見光光譜不太會增加乳癌風險，且與前列腺癌呈負相關[17]。
人工照明不僅威脅著人類的健康，還破壞了野生動物的棲息地，更對其生命階段和關鍵行為活動產生不利影響。有研究表明，人工光源會影響海龜築巢[18]，改變母龜產卵行為，並會導致剛孵化的小海龜迷失方向，從而無法順利返回大海[19]~[21]。昆蟲學家認為，人工光源是昆蟲減少的驅動因素[22][23]。白熾燈泡產生的中等光照水平（8-40勒克斯）會顯著減少了白蟻產卵的數量[24]。人工光照還會破壞蛾的繁殖、幼蟲發育和蛹滯育[25]。同樣，光汙染也會擾亂植物的晝夜節律，影響其發芽、開花、休眠、落葉等生長過程，進而影響到整個生態系的平衡[26]。植物物種對人工光汙染更敏感，當人工照明越亮時，物候進展受到的阻礙越明顯，甚至出現延遲現象，如出葉和開花的物候期顯著延遲[27]。
另外，夜晚不必要的照明會造成能源浪費，排放更多的二氧化碳，給生態環境造成更大壓力。據國際暗夜組織估算，美國每年至少有30%的戶外照明被浪費，大部份是沒有遮蔽的燈，造成每年2 100萬t二氧化碳(CO2)的排放量。要抵消這部份的二氧化碳，則需要每年種植8.75億棵樹[28]。而夜間照明釋放的熱量也會加劇了城市「熱島效應」[29]。
隨著城市化行程的加速，智慧城市的持續推進，光汙染不斷加劇。因此，我們需要加強治理光汙染、守護好黑暗夜空。那麽，在生活中，我們如何減少光汙染呢？
首先，關閉不必要的照明，縮短戶外照明時間。根據最近的流行病學研究，不僅輻射強度，而且光汙染的光譜和時間，都是影響健康的潛在因素[30]。戶外照明會影響夜行動物的行動，比如覓食和遷徙等。
其次，盡量使用暖色光的燈，遠離藍光，健康用眼。LED燈由於其節能性而被廣泛用來替代傳統的窄光譜照明，如鈉燈（發出暖色光）。但LED燈通常會發出冷色光，而藍光已經被證明可以降低人類褪黑激素的水平[31]。另外，電腦、iPad、手機和熒光棒等產品也存在藍光。有研究表明，在常規電腦螢幕亮度藍光暴露下，2h即可出現角膜上皮輻射損傷[32]。
再次，建議使用帶有遮蔽罩的戶外照明燈具。不必要的人工照明產生的眩光是一個日益嚴重的問題[33]。遮蔽罩可以防止光線超過一定範圍，盡量減少眩光以及對人類和環境的有害影響。
最後，在夜晚行車不要濫用遠光燈。過於明亮的照明環境會對司機的視覺造成不良影響，引起視覺疲勞，容易引發交通事故[34]。
文/藍天 審/趙玉萍 編輯/Leah
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