1000集 TED-ED 【中英CC字幕】| 认真刷完英语水平直接起飞！

1. "You are breathing patiently;it is beauutiful sound.It is your life"-Mary Oliver,"Qxygen"

2.Take a deep breath.In that single intake of air单次进气量,your lungs swelled with充满 roughly大约 25 sextillion10^36 molecules,ranging from compounds化合物 produced days ago,to those formed billions十亿 of years in the past.

3.In fact,many of the molecules you're breathing were likely可能exhaled呼出 by members of ancient civilizations and innumerable无数的 humans since到现在，至今.

4.But what exactly究竟 are we all breathing?

5.Roughly大约 78% of Earth's atmosphere大气 is composed of nitrogen氮 generated产生 by volcanic activity火山活动 deep beneath the planet's crust地壳.

5.The next major ingredient成分 is oxygen,accounting for占 21% of Earth's air.

6.While尽管 oxygen molecules have been around 存在的（形容词）as long as Earth's oceans,oxygen gas didn't appear until ocean dwelling microorganisms海洋栖息微生物 evolved进化 to produce it.

7.Finally,0.93% of our air is argon氩,a molecule formed from the radioactive decay放射性衰变 of potassium钾 in Earth's atmosphere,crust地壳,and core地核.

8.Together,all these dry gases干燥气体 make up 99.93% of each breath you take.

9.Depending on取决于 when and where you are,the air may also contain some water vapor水蒸气.

10.But even more variable存在变数的 is that remaining 剩下的0.07%,which contains a world of possibilities 一个充满可能性的世界.

11.This small slice of air is composed of numerous许多 small particles粒子 including pollen花粉,fungal spores真菌孢子 and liquid droplets液滴,alongside以及 trace gases微量气体 like methane甲烷 and carbon dioxide二氧化碳.

12.The specific cocktail混合物 of natural and man-made人为的 compounds化合物 changes dramatically巨大的 from place to place.

13.But no matter 不论where you are,0.07% of every breath you take likely可能 contains man-made pollutants——potentially可能 including toxic compounds 有毒化合物that can cause lung disease,cancer and even DNA damageDNA损伤.

14.There's a wide variety of很多的 known pollutants已知污染物 but they all fall into two categories.分为两类

15.The first are primary pollutants.主要污染物

16.These toxic compounds are directly emitted排放 from a man-made or naturally occurring source.天然来源

17.However,they don't always come from the places you'd expect.

18.Some large factories mostly 大多 generate 产生water vapor水蒸气，with only small quantities of 少量 pollutants mixed in混入.

19.Conversely相反,burning wood or dung粪便 can create polycyclic aromatic hydrocarbons多环芳香烃;dangerous compounds that have been linked to与...有关 several types of 几种cancer,as well as 以及long-term 长期的DNA damage.

20.In all cases就所有情况而言，pollutants interact with 与...相互作用regional 区域weather patterns天气模式 and topography地形,which can keep compounds local 使...留在当地or spread them kilometers away.

21.When these molecules travel through the air在空气中传播， a transformation 转变occur出现s.

22.Natural compound化合物s called oxidant氧化剂s,formed by oxygen and sunlight,break down 分解the pollutant污染物s.

23.Sometimes,these reaction反应s make pollutants more easily washed out by rain被雨水冲走.

24.But in other cases在其他情况下,they result in 导致even more toxic secondary pollutant二次污染物s.

25.For example,when factories burn coal,they release 释放high concentration浓度s of sulfur oxides氧化硫.

26.These molecules oxidize氧化 to form sulfates硫酸盐,which condense 凝聚with water vapor in the air to form a bianket of 大量的fine particles细小颗粒that impair 损害visibility 能见度and cause severe lung damage损伤.

27.This so-called 所谓的sulfurous smog 硫磺烟雾was well-known 广为人知in 20th century London and continues to 继续plague 困扰cities like Beijing.

28.Since the advent of cars,another 另一种secondary pollutant 二次污染物has taken center stage占据中心位置.

29.Exhaust尾气 from fossil fuel-burning化石燃料燃烧 vehicles 交通工具release释放s nitrogen oxides 氮氧化物and hydrocarbons碳氢化合物 which react to form反应形成 ozone臭氧.

30.And while虽然 some ozone in the upper atmosphere 高层大气 helps shield us from保护us免受 ultraviolet rays紫外线, on the ground,this gas can form alongside secondary particles次级粒子 and create photochemical smog.光化学烟雾

31.This brown fog can be found covering densely packed cities人口密集城市,making seeing difficult视物困难 and breathing hazardous呼吸危险.

32.It also contributes to导致 climate change by trapping heat 吸收热量in the atmosphere.

33.In recent decades近几十年来,industrial activity has contributed to huge spike大幅上升 in various trace gas 微量气体emission排放s,fundamentally 从根本上changeing the air we all breathe.

34.Many place have already responded with 采取countermeasure反制措施s.

35.Most cars produced since the 1980's are equipped with catalytic converters催化式排气净化器that reduce the emission of carbon monoxide 一氧化碳and nitrogen oxides氮氧化物.

36.And today,place like Beijing are battling smog 雾霾by electrify电气化ing their energy infrastructure能源基础设施 and limiting automobile 汽车emissions altogether.

37.But while 虽然moving away from 远离fossil fuels is essential必要的,there's no universal 通用的remedy 治疗方法for air pollution.

38.Different regions need to respond with 采取unique regulation规章s that account for应对 their local pollutants.

39.Because no matter where you live,we all share the same air.