1987年11月，世界衛生組織在日本東京舉行的第6屆吸菸與健康國際會議上建議把每年的4月7日定為世界無菸日（World No Tobacco Day），並從1988年開始執行，但從1989年開始，世界無菸日改為每年的5月31日，因為第二天是國際兒童節，希望下一代免受菸草危害。香菸究竟會對健康會造成哪些危害，是我們必須要了解的。
Cigarettes aren't good for us.
香菸對我們無益。
That's hardly news - we've known about the dangers of smoking for decades.
這已經不算是新聞了——幾十年來我們一直都知道抽菸的危害。
But how exactly do cigarettes harm us?
但是香菸到底是怎麼傷害我們的？
Let's look at what happens as their ingredients make their way through our bodies, and how we benefit physically when we finally give up smoking.
讓我們看看，當香菸的成分進入我們的身體時，會發生什麼，以及戒菸後對身體有什麼好處。
With each inhalation, smoke brings its more than 5,000 chemical substances into contact with the body's tissues.
每吸一次煙，煙霧會攜帶五千種以上的化學成分，和身體組織接觸。
From the start, tar, a black, resinous material, begins to coat the teeth and gums, damaging tooth enamel, and eventually causing decay.
從一開始，焦油，一種黑色的樹枝材料，會覆蓋牙齒和牙齦，損傷牙釉質，最終導致腐爛。
Over time, smoke also damages nerve-endings in the nose, causing loss of smell.
隨著時間的推移， 煙霧也會傷害鼻子中的神經末梢，導致嗅覺丟失。
Inside the airways and lungs, smoke increases the likelihood of infections, as well as chronic diseases like bronchitis and emphysema.
在氣道和肺內部，抽菸會增加感染的可能性，以及慢性疾病，比如支氣管炎和肺氣腫。
It does this by damaging the cilia, tiny hairlike structures whose job it is to keep the airways clean.
它是通過破壞纖毛來實現的，微小的毛髮狀結構，其作用是保持氣道清潔。
It then fills the alveoli, tiny air sacs that enable the exchange of oxygen and carbon dioxide between the lungs and blood.
然後填充肺泡，微小的空氣囊能使氧氣和二氧化碳在肺部和血液之間交換。
A toxic gas called carbon monoxide crosses that membrane into the blood, binding to hemoglobin and displacing the oxygen it would usually have transported around the body.
一個叫一氧化碳的毒氣穿過膜進入血液，使血紅蛋白結合，以及置換氧氣，它通常會在身體周圍傳播。
That's one of the reasons smoking can lead to oxygen deprivation and shortness of breath.
這就是吸菸可導致缺氧和呼吸急促的原因之一。
Within about 10 seconds, the bloodstream carries a stimulant called nicotine to the brain, triggering the release of dopamine and other neurotransmitters including endorphins that create the pleasurable sensations which make smoking highly addictive.
在大概十秒的範圍內，血液攜帶一種叫做尼古丁的興奮劑進入大腦，多巴胺和其他神經遞質釋放的觸發，包括內啡肽，會通過製造愉快的感覺，使吸菸上癮。
Nicotine and other chemicals from the cigarette simultaneously cause constriction of blood vessels and damage their delicate endothelial lining, restricting blood flow.
香菸攜帶的尼古丁和其他化學成分，會使血脈縊縮，同時損傷它們脆弱的內皮細胞，限制血流。
These vascular effects lead to thickening of blood vessel walls and enhance blood platelet stickiness, increasing the likelihood that clots will form and trigger heart attacks and strokes.
這些血管效應會導致血脈壁增厚和提高血小板的黏度，提高血塊形成的可能性，引發心臟病發作和中風。
Many of the chemicals inside cigarettes can trigger dangerous mutations in the body's DNA that make cancers form.
香菸裡面許多的化學成分可以引發嚴重的基因突變，使癌症形成。
Additionally, ingredients like arsenic and nickel may disrupt the process of DNA repair, thus compromising the body's ability to fight many cancers.
此外， 砷和鎳等成分也許會破壞DNA修復的過程，從而損害身體對抗許多癌症的能力。
In fact, about one of every three cancer deaths in the United States is caused by smoking.
事實上，在美國三分之一的癌症死亡是吸菸導致的。
And it's not just lung cancer.
而且不只是肺癌。
Smoking can cause cancer in multiple tissues and organs, as well as damaged eyesight and weakened bones.
吸菸既可以使多個組織和器官致癌，又可以使視力受損，甚至骨骼變弱。
It makes it harder for women to get pregnant.
它使女性受孕變得更加困難。
And in men, it can cause erectile dysfunction.
另外會使男性有勃起功能的障礙。
But for those who quit smoking, there's a huge positive upside with almost immediate and long-lasting physical benefits.
但是對於那些戒菸的人來說，有一個巨大的益處，一個幾乎可以立即獲得，且對身體持續良久的益處。
Just 20 minutes after a smoker's final cigarette, their heart rate and blood pressure begin to return to normal.
吸菸者在抽完最後一支煙的二十分鐘後，他們的心跳和血壓就開始恢復正常了。
After 12 hours, carbon monoxide levels stabilize, increasing the blood's oxygen-carrying capacity.
十二個小時之後， 一氧化碳達到標準，增加血液攜氧能力。
A day after ceasing, heart attack risk begins to decrease as blood pressure and heart rates normalize.
停止一天之後，血壓和心跳回歸正常，從而降低心臟病突發的危險。
After two days, the nerve endings responsible for smell and taste start to recover.
兩天之後，負責嗅覺和味覺的神經末梢開始恢復。
Lungs become healthier after about one month, with less coughing and shortness of breath.
肺在大概一個月之後變得更健康，咳嗽和呼吸急促減少。
The delicate hair-like cilia in the airways and lungs start recovering within weeks, and are restored after 9 months, improving resistance to infection.
幾周內，毛髮似的纖毛在呼吸道和肺中開始恢復，九個月後結束修復， 提高抗感染能力。
By the one-year anniversary of quitting, heart disease risk plummets to half as blood vessel function improves.
戒菸後的一周年，心臟病風險驟然跌落到一半，同時血管功能改善。
Five years in, the chance of a clot forming dramatically declines, and the risk of stroke continues to reduce.
五年內，血栓形成的機率大大下降，中風風險持續減少。
After ten years, the chances of developing fatal lung cancer go down by 50%, probably because the body's ability to repair DNA is once again restored.
十年後， 罹患致命肺癌的機會下降到50%，大概是因為又一次恢復身體修復DNA的能力。
Fifteen years in, the likelihood of developing coronary heart disease is essentially the same as that of a non-smoker.
十五年內，患冠心病的可能性基本上和非吸菸者相同。
There's no point pretending this is all easy to achieve.
假裝這一切都很容易實現是沒有意義的。
Quitting can lead to anxiety and depression, resulting from nicotine withdrawal.
戒菸可導致焦慮和抑鬱，由於戒斷尼古丁造成的。
But fortunately, such effects are usually temporary.
但幸運的是，這種影響通常是暫時的。
And quitting is getting easier, thanks to a growing arsenal of tools.
感謝越來越多的工具庫， 戒菸變得越來越容易。
Nicotine replacement therapy through gum, skin patches, lozenges, and sprays may help wean smokers off cigarettes.
口香糖替代尼古丁的療法，皮膚貼片，含片，和噴霧可以幫助吸菸者戒菸。
They work by stimulating nicotine receptors in the brain and thus preventing withdrawal symptoms, without the addition of other harmful chemicals.
它們通過刺激大腦中的尼古丁受體來起作用，從而防止戒斷症狀，不含其他有害化學物質。
Counselling and support groups, cognitive behavioral therapy, and moderate intensity exercise also help smokers stay cigarette-free.
諮詢和互助小組，認知行為療法，和中等強度運動也可以幫助吸菸者保持不吸菸的狀態。
That's good news, since quitting puts you and your body on the path back to health.
這是一個好消息，從戒菸讓你和你的身體回到健康的道路上開始。