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  • On July 26, 1943,

    1943年7月26號

  • Los Angeles was blanketed by a thick gas that stung people's eyes

    洛杉磯被一層濃厚、使人眼睛感到刺痛

  • and blocked out the Sun.

    且遮蔽陽光的氣體所壟罩

  • Panicked residents believed their city had been attacked using chemical warfare.

    驚恐的居民相信他們的城市被化學武器攻擊了

  • But the cloud wasn't an act of war.

    但這些烏雲並不是出於戰爭

  • It was smog.

    那是霧霾

  • A portmanteau of smoke and fog,

    就是煙和霧混合構成的詞

  • the word smog was coined at the beginning of the 20th century

    霧霾這個詞是在20世紀初被創造出來的

  • to describe the thick gray haze that covered cities

    來解釋壟罩城市的厚重灰霾

  • such as London,

    像是倫敦、

  • Glasgow,

    格拉斯哥、

  • and Edinburgh.

    以及愛丁堡

  • This industrial smog was known to form

    這些工業的煙霧

  • when smoke from coal-burning home stoves and factories

    是由家中爐子和工廠燒煤

  • combined with moisture in the air.

    混合濕氣進到大氣中

  • But the smog behind the LA panic was different.

    但洛杉磯的霾害不一樣,

  • It was yellowish with a chemical odor.

    是微黃色的,且混雜著化學臭味

  • Since the city didn't burn much coal, its cause would remain a mystery

    但這個城市並沒有燒很多煤,它的成因一直是個謎

  • until a chemist named Arie Haagen-Smit identified two culprits,

    直到一位名叫 Arie Haagen-Smit 的化學家發現了兩個兇手

  • volatile organic compounds, or VOCs,

    揮發性的有機化合物,或稱 VOCs,

  • and nitrogen oxides.

    以及一氧化二氮

  • VOCs are compounds that easily become vapors

    VOCs 是一種容易揮發

  • and may contain elements, such as carbon,

    可能包含其他物質的混合物,像是碳、

  • oxygen,

    氧、

  • hydrogen,

    氫、

  • chlorine,

  • and sulfur.

    和硫磺

  • Some are naturally produced by plants and animals,

    有些是由動植物自然產生的,

  • but others come from manmade sources,

    但其他則是人造的

  • like solvents,

    像是溶劑、

  • paints,

    塗料、

  • glues,

  • and petroleum.

    和石油

  • Meanwhile, the incomplete combustion of gas in motor vehicles

    同時,摩托車未燒完全的氣體

  • releases nitrogen oxides.

    會釋放一氧化二氮

  • That's what gives this type of smog its yellowish color.

    那就是讓霧霾變黃色的原因

  • VOCs and nitrogen oxide react with sunlight

    VOCs 和一氧化二氮對陽光起反應

  • to produce secondary pollutants called PANs and tropospheric,

    並製造出第二種污染物,稱作 PANs 和位於對流層

  • or ground level, ozone.

    或是陸地上的臭氧

  • PANs and ozone cause eye irritation and damage lung tissue.

    PANs 和臭氧會刺激眼睛,並造成肺部的傷害

  • Both are key ingredients in photochemical smog,

    這些都是光化學霧霾的主要成分

  • which is what had been plaguing LA.

    也是洛杉磯的霾害來源

  • So why does smog affect some cities but not others?

    那為何霾害只出現在幾個城市呢?

  • Both industrial and photochemical smog combine manmade pollution

    工業和光化學霧霾都包含了

  • with local weather and geography.

    當地天氣及地理環境的人造污染

  • London's high humidity made it a prime location for industrial smog.

    高濕度讓倫敦成了累積工業霧霾的地方

  • Photochemical smog is strongest in urban areas with calm winds

    光化學霧霾在有著微風、

  • and dry, warm, sunny weather.

    乾燥、溫暖、晴天的都會地區最為嚴重

  • The ultraviolet radiation from sunlight provides the energy necessary

    太陽的紫外射線提供了必需的能量

  • to breakdown molecules that contribute to smog formation.

    來分解形成霧霾的分子

  • Cities surrounded by mountains, like LA,

    像是洛杉磯這種山地環繞的城市

  • or lying in a basin, like Beijing,

    或像是北京這種坐落在盆地的城市

  • are also especially vulnerable to smog since there's nowhere for it to dissipate.

    也都特別容易受霾害,因為沒有地方可以讓霧霾消散

  • That's also partially due to a phenomenon known as temperature inversion,

    其中一部分原因,是所謂的逆溫現象所造成的

  • where instead of warm air continuously rising upward,

    就是熱空氣不斷的上升,

  • a pollution-filled layer of air remains trapped near the Earth's surface

    被汙染的空氣層被囚禁在地球表面

  • by a slightly warmer layer above.

    被一層輕薄的暖空氣覆蓋在上面

  • Smog isn't just an aesthetic eyesore.

    霧霾不只是造成朦朧美

  • Both forms of smog irritate the eyes,

    這些霾的形成會刺激眼睛、

  • nose,

    鼻子

  • and throat,

    和喉嚨

  • exacerbate conditions like asthma and emphysema,

    還會使氣喘、肺氣腫病情加劇

  • and increase the risk of respiratory infections like bronchitis.

    並增加肺部感染的危險,像是支氣管炎

  • Smog can be especially harmful to young children and older people

    霧霾對小孩及老人會有特別大的傷害,

  • and exposure in pregnant women has been linked to low birth weight

    孕婦暴露在霾害中會使肚子裡的寶寶體重減輕

  • and potential birth defects.

    和潛在的缺陷

  • Secondary pollutants found in photochemical smog

    光化學霧霾中的第二種汙染物質

  • can damage and weaken crops and decrease yield,

    會傷害作物,使產量減低

  • making them more susceptible to insects.

    並讓作物更容易遭受蟲害

  • Yet for decades, smog was seen as the inevitable price of civilization.

    到目前幾十年,霾害看來是文明無法避免付出的代價

  • Londoners had become accustomed to the notorious pea soup fog

    倫敦人已經習慣了惡名昭彰的霧霾

  • swirling over their streets until 1952,

    盤旋在他們的街道間

  • when the Great Smog of London shut down all transportation in the city for days

    直到1962年倫敦煙霧事件,迫使所有交通工具停止

  • and caused more than 4,000 respiratory deaths.

    並造成超過4000人因呼吸疾病死亡

  • As a result, the Clean Air Act of 1956

    因此,1956年的清潔空氣法

  • banned burning coal in certain areas of the city,

    禁止在城市的特定區域燒煤

  • leading to a massive reduction in smog.

    這大量減少了霧霾

  • Similarly, regulations on vehicle emissions and gas content in the US

    美國也對交通工具的排氣量頒布了類似的法案

  • reduced the volatile compounds in the air and smog levels along with them.

    減少空氣中的揮發化合物及霧霾的汙染程度

  • Smog remains a major problem around the world.

    霧霾在世界上是個很大的問題,

  • Countries like China and Poland that depend on coal for energy

    像是中國、波蘭這些仰賴煤炭作為能源的國家

  • experience high levels of industrial smog.

    遭受嚴重的工業霾害

  • Photochemical smog and airborne particles from vehicle emissions

    交通工具產生的光化學霾害和懸浮粒子

  • affect many rapidly developing cities,

    影響許多快速發展的城市

  • from Mexico City and Santiago

    從墨西哥市、聖地牙哥

  • to New Delhi and Tehran.

    到新德里和德黑蘭

  • Governments have tried many methods to tackle it,

    許多政府已經嘗試了許多解決方法

  • such as banning cars from driving for days at a time.

    像是規定一天車輛行駛的特定時間

  • As more than half of the world's population crowds into cities,

    當超過世界一半的人口擠進城市

  • considering a shift to mass transit and away from fossil fuels

    就要思考如何排除大量化石燃料汙染

  • may allow us to breathe easier.

    才能使我們呼吸得更輕鬆

On July 26, 1943,

1943年7月26號

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B2 中高級 中文 美國腔 TED-Ed 霧霾 城市 汙染 洛杉磯 空氣

【TED-Ed】霧霾科學 (The science of smog - Kim Preshoff)

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    mike87520 發佈於 2018 年 02 月 16 日
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