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單次進(jìn)氣量,your lungs swelled with充滿 roughly大約 25 sextillion10^36 molecules,ranging from compounds化合物 produced days ago,to those formed billions十億 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無(wú)數(shù)的 humans since到現(xiàn)在，至今.

4.But what exactly究竟 are we all breathing?

5.Roughly大約 78% of Earth's atmosphere大氣 is composed of nitrogen氮 generated產(chǎn)生 by volcanic activity火山活動(dòng) deep beneath the planet's crust地殼.

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

6.While盡管 oxygen molecules have been around 存在的（形容詞）as long as Earth's oceans,oxygen gas didn't appear until ocean dwelling microorganisms海洋棲息微生物 evolved進(jìn)化 to produce it.

7.Finally,0.93% of our air is argon氬,a molecule formed from the radioactive decay放射性衰變 of potassium鉀 in Earth's atmosphere,crust地殼,and core地核.

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

9.Depending on取決于 when and where you are,the air may also contain some water vapor水蒸氣.

10.But even more variable存在變數(shù)的 is that remaining 剩下的0.07%,which contains a world of possibilities 一個(gè)充滿可能性的世界.

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

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

13.But no matter 不論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損傷.

14.There's a wide variety of很多的 known pollutants已知污染物 but they all fall into two categories.分為兩類(lèi)

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.天然來(lái)源

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

18.Some large factories mostly 大多 generate 產(chǎn)生water vapor水蒸氣，with only small quantities of 少量 pollutants mixed in混入.

19.Conversely相反,burning wood or dung糞便 can create polycyclic aromatic hydrocarbons多環(huán)芳香烴;dangerous compounds that have been linked to與...有關(guān) several types of 幾種cancer,as well as 以及long-term 長(zhǎng)期的DNA damage.

20.In all cases就所有情況而言，pollutants interact with 與...相互作用regional 區(qū)域weather patterns天氣模式 and topography地形,which can keep compounds local 使...留在當(dāng)?shù)豲r spread them kilometers away.

21.When these molecules travel through the air在空氣中傳播， a transformation 轉(zhuǎn)變occur出現(xiàn)s.

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

23.Sometimes,these reaction反應(yīng)s make pollutants more easily washed out by rain被雨水沖走.

24.But in other cases在其他情況下,they result in 導(dǎo)致even more toxic secondary pollutant二次污染物s.

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

26.These molecules oxidize氧化 to form sulfates硫酸鹽,which condense 凝聚with water vapor in the air to form a bianket of 大量的fine particles細(xì)小顆粒that impair 損害visibility 能見(jiàn)度and cause severe lung damage損傷.

27.This so-called 所謂的sulfurous smog 硫磺煙霧was well-known 廣為人知in 20th century London and continues to 繼續(xù)plague 困擾cities like Beijing.

28.Since the advent of cars,another 另一種secondary pollutant 二次污染物has taken center stage占據(jù)中心位置.

29.Exhaust尾氣 from fossil fuel-burning化石燃料燃燒 vehicles 交通工具release釋放s nitrogen oxides 氮氧化物and hydrocarbons碳?xì)浠衔?which react to form反應(yīng)形成 ozone臭氧.

30.And while雖然 some ozone in the upper atmosphere 高層大氣 helps shield us from保護(hù)us免受 ultraviolet rays紫外線, on the ground,this gas can form alongside secondary particles次級(jí)粒子 and create photochemical smog.光化學(xué)煙霧

31.This brown fog can be found covering densely packed cities人口密集城市,making seeing difficult視物困難 and breathing hazardous呼吸危險(xiǎn).

32.It also contributes to導(dǎo)致 climate change by trapping heat 吸收熱量in the atmosphere.

33.In recent decades近幾十年來(lái),industrial activity has contributed to huge spike大幅上升 in various trace gas 微量氣體emission排放s,fundamentally 從根本上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催化式排氣凈化器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 霧霾by electrify電氣化ing their energy infrastructure能源基礎(chǔ)設(shè)施 and limiting automobile 汽車(chē)emissions altogether.

37.But while 雖然moving away from 遠(yuǎn)離fossil fuels is essential必要的,there's no universal 通用的remedy 治療方法for air pollution.

38.Different regions need to respond with 采取unique regulation規(guī)章s that account for應(yīng)對(duì) their local pollutants.

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