The Fog That Killed 12,000 People

[♪ INTRO] London is famously foggy. Sometimes that can mean a wistful stroll or
another excuse for a cuppa tea, but when fog mixes with the smoke and chemicals produced
by industry, it becomes something new: smog. And for a couple of centuries, London’s
smog could kill. Really bad smogs could kill a thousand people
in a few days, but no one did much about it until 1952, when a five-day smog in London
killed an estimated twelve thousand people. It was called The Great Smog of London, and
it helped wake up the country and the world to the dangers of unrestricted pollution. Fog is just a cloud that forms down here on
the ground, which by itself isn’t that bad; you might not be able to
see well when you’re driving, or you might not be able to
land your plane, but it’s nice. But clouds can act like sponges, forming around
and trapping whatever’s already in the air. This wasn’t a problem until
the 1200s, when a lot of London switched from wood to
coal for heating their homes. Burning coal creates soot and smoke,
which can irritate your lungs, and also creates poisons like
sulfur dioxide and carbon monoxide. Sulfur dioxide, which is a sulfur atom bonded
to two oxygen atoms, reacts with water to form sulfuric acid, which can harm your internal
organs, as you might imagine. And carbon monoxide, which is one carbon and
one oxygen, binds with the hemoglobin in your blood to stop oxygen from
getting around your body. So when London started burning coal, all the
smoke and chemicals mixed with the natural fog, and it became thicker
and darker as years passed. It wasn’t a health crisis at first, but people did complain that
the smoke smelled terrible. And this was back in the 1200s, when everything
smelled terrible already. But it was easier to keep burning coal than
to switch back to wood, so for centuries, they just accepted the occasional thick, dark,
smelly cloud hanging over the city. As you do. Things really got dangerous when the Industrial
Revolution happened in the 1700s. Because now, coal wasn’t just heating homes. It powered huge factories throughout the city,
and all that extra smoke and soot made the air in London’s fogs much darker. It became so common that a physician named
Harold Antoine Des Voeux invented the term “smog” to describe it. Really smoggy days completely blacked out
the center of the city, so that you couldn’t see more than a few meters ahead of you, even
in the middle of the day. The soot also irritated people’s lungs,
causing illnesses like bronchitis to become more common. Some people even suffocated from breathing
so much smoke or the poisons in the air. Individual smogs in 1873 and 1892 each killed
over a thousand humans and livestock. And we don’t even know how many people died
early from collecting soot in their lungs over the course of their lives. But coal kept London flourishing,
so nobody did anything to stop it. Then came The Great Smog. On December 5, 1952, a thick fog rolled in
and mixed with London’s dirty air, just like it did most winters. But this time, high-pressure
weather systems surrounded London and kept the cloud from moving on. So an especially dense, black smog stopped
on London for five miserable days. The smog was so thick that flights were grounded,
most public transportation was canceled, trains collided, and theaters
and movies stopped, because people couldn’t see
what they were watching. This is difficult to imagine, this was 1952,
not that long ago. An estimated four thousand people died in
those five awful days before the smog dissipated. A lot of them suffocated because their lungs
were inflamed from breathing in so much soot. And with sulfur dioxide from the burning coal
reacting with water vapor in the smog, Londoners also spent those five days
breathing air full of sulfuric acid. That and the smoke contributed to
respiratory and other health problems, which killed around another
eight thousand people in the following months. Ultimately, roughly one in a thousand Londoners
died because of The Great Smog. Some people argued afterward that the spike
in deaths was due to a flu epidemic, but scientists have investigated that in all sorts of ways,
and it’s really unlikely that the flu could have been anywhere near as devastating
as the smog itself. Four years later, Parliament finally passed
a Clean Air Act that dictated what kinds of fuels could
be burned within the city. It and other laws have helped rein in the
smog problem in London. But even today, London’s air pollution lowers
the life expectancy of a lot of people, and is indirectly linked to
tens of thousands of early deaths every year throughout the United Kingdom. Despite the Great Smog’s devastation,
it took a while for other industrial powerhouses to take the hint. New York City had a series of smogs in the
1960s that affected more than 16 million people, and black, soot-filled rain coated Boston
around the same time. But eventually, lawmakers
around the world stepped in. Starting in the 1970s, laws got serious about
limiting air pollution, forcing car companies to make more efficient engines, and factories
to produce fewer emissions. Because it turns out, turning air into poison,
is not a great idea. Thank you for watching this episode of
SciShow, you’re great. And a special thanks to all of our patrons
on Patreon for making it happen! If you’d like to help us make more episodes
like this, so that everybody can have them, regardless of whether they can pay,
you can go to, and if you just want to support us by watching,
please do that at [♪ OUTRO]

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100 Responses

  1. xcrafter_40 says:

    I thought it said frog

  2. Ratio says:

    I read that as frog

  3. Baran Orak says:

    I clicked on this because at a glance I read killer frog

  4. Sandra Hottel says:

    smog uses cover


  5. Aditya Dixit says:

    I think, after the deaths of more than millions people, Indians will make laws for atmospheric cleanliness.

  6. Rektrak Nuns says:

    The mist in a nut shell

  7. Augustine M says:

    The Frog that Killed 12,000 People

  8. xcheeztx says:

    I thought it said the frog that killed 12,000 people. I was about to change my profile picture.

  9. M. Douglas says:

    Well of course Smaug can kill 12,000 people. He's a dragon! Oh Wait… Smog.

  10. holleysdotcom says:


  11. Sapphire Rose says:

    The great frog

  12. Ted Phillips says:

    Charles Lightoller, most senior of the Titanic's officers to survive the ship'ssinking, died of heart failure during the London smog.

  13. Jean-Luc Martel says:

    Just saw this on The Crown literally made my stomach churn. An entire city turns into a gas chamber. My mom would have been there if she wasn't from Birmingham.

  14. SteepVisions says:

    If you're going to refer to it as smog in your video you should do the same in your title. clickbait

  15. Blah Blahsen says:

    human beings really are a cancer on this world arent we?

  16. Cyberus Morphous says:

    too bad godzilla wasnt around or he could have fought the pollution

  17. Remi says:

    i read fog as frog

  18. Michelle Vlogs says:

    what could people hear during the great smog?

  19. Okoboji says:

    The Beatles’ I Am The Walrus song reference about getting a tan while standing in the English rain is in reference to the smog problem.

  20. David Eduardos says:

    Hey, mate, have you wondered about creating a video about another important event that took place in London in the 19th century? I'm talking about "The Great Stink of London of 1853". That's such an interesting part of Environmental History.
    Thanks for the video, you smashed it.

  21. Lorisa214 says:

    The Crown did an episode on this!

  22. smurfyday says:

    Now we're removing all those regulations. Thanks, Trumpsters.

  23. CoolSaitama HD says:

    Thats Scary

  24. jerrod stephenson says:

    Lucky that fog didn't have a knife

  25. networkdeath1 says:

    Hey now, the Brits got together and largely solved this terrible plague. Give them credit. And they did it just in time to begin bringing in millions of religious psychopaths from the 4th century (after abandoning their own faith), who pray 5X/day to Mecca that all Anglo-Saxons be slaughtered.
    So stop criticizing the British, they got this!!!!

  26. Nurs St Olaves boii says:

    is that the dude who does the chemistry crash courses?

  27. Max Covfefe says:

    Dammit! I thought this was gonna be about a killer frog. Now I'm disappointed.

  28. Who wants to talk about murders! says:

    Now I face out, I hold out.
    I reach out to the truth of my life
    Seeking to seize on the whole moment, yeah

    Naked truth lies only if you realize
    Appearing in nobody's eyes till they sterilize
    Stop the guerrilla warfare to keep it fair
    Bro change your rage to a smarter greater cause

    You know the stake is high stardom is near
    Those who sympathized you die killers pass by
    Do not waste your time in hating flirting guys
    Use your might to AIs do justice to them all

    Now I face out I hold out
    I reach out to the truth of my life
    Seeking to seize on the whole moment to now break away

    Oh God let me out
    Can you let me out?
    Can you set me free from this dark inner world?
    Save me now

    Last beat in the soul

  29. LongTall Texan says:

    02:17 … You call that fog and smog?… Have you ever been to Los Angeles? how about the central California Valley?

  30. Sereda Hawke says:

    The Great Smog of London sounds like a nickname for Sherlock, meant to describe his ability to shut down happiness in an area.

  31. Omkar Thite says:

    Watching for evs exam ! Wish me luck

  32. William Days says:

    It happened in the United States as well; in 1948, Donora, Pennsylvania, south east of Pittsburgh. For 5 days or so, around Halloween, a temperature inversion trapped industrial smoke, automobile exhaust and other pollutants in the air. It hung over the river valley and the town like a blanket. It was like night around the clock. Visibility was practically zero. It became quite serious. There was loss of life, especially the sick, the elderly and the very young. The steel mills kept on belching smoke in spite of the growing health crisis. It was said that the furnaces were too costly to shut down and then later restart once the inversion lifted. They finally relented, I believe, in the end and shut down when people started dying!! Look it up. It's a interesting story. Hank, you should produce a video on this, it would fit right in. Just a thought…

  33. FarmYard Gaming says:


  34. Alexandra Muchura-Mensah says:

    to bad

  35. TheBeingReal says:

    The GOP loves pollution.

  36. Mr.Rittichai Chanyotha says:

    ตามมาจาก Point Of View

  37. Barbara Cunningham says:

    I remember visiting London as a child and experiencing a smog. It smelt awful and at one stage my father could not read a street name so mum got out of the car and had to go right up to the post to be able to read the sign. The fog was really yellowish and horrible.

  38. LeatherNeck 1833 says:

    Hummm, smog kills 12K people within months…takes 4 years for someone to do something about it.
    Meanwhile, several people are bitten and/or killed by sharks in a couple of days…people take action immediately and kill sharks by the thousands. Sounds about right for our race.
    If we cause the problem then we are slow to correct it; if nature causes the problem we are Johnny on the spot.

  39. john turner says:

    London is famously foggy. Except the majority of the time when it’s not


    I thought it said The Frog That Killed 12,000 People

  41. BabyPinkSnail says:

    Persona 4 joke

  42. wolcek says:

    "fish gotta swim and birds gotta fly,
    but they don't last long if they try"

  43. The daily topic and gaming says:

    China*huh what is this Clean Air you speak of?

  44. Zes says:

    no such thing as every thing smelt terrible or would do that or miserable, do, be any nmw and any b perfx

  45. alfred william says:

    Aircraft pollution is out of control, Heathrow airport consumes 25+million litres of kerosene a day. London has six airports they consume so much kerosene it would be impossible to transport it by road, tyre particles and brake dust from landing and taking off is unforgivable, the lies and proper gander blaming the motorist is disgusting, no particulate filters on these dirty filthy giant oil burners, they cause so much pollution in the atmosphere not only are they giant kerosene heaters they are rainmakers they are turning sulphur dioxide into sulphuric acid that means you are flying in a sea of acid, jet engines are suffering from metal fatigue and corrosion the air in the aircraft cabins is toxic, pilots and cabin crew have one of the highest rates of cancer out of all occupations, rockets burnt the whole in the ozone layer and they blame the public on the ground you could not make it up, the co2 scam ,dry ice is co2 the earth's coolant,so much truth is being covered up, one point nine million domestic house old boilers use kerosene oil no particulate filters why not.

  46. olof says:

    Dammit the children of atom are at it again

  47. Vickie Gilman says:

    Look on the bright side, The Great Smog woke up the world because it killed so many people.

  48. Provoganda says:

    No one did much about it. People. We suck.

  49. c0c0nutBeans says:

    The White Whale made us think people died.

  50. Ry Serna says:

    pretty sure this video sucks ass too

  51. Adapple says:

    I thought it said frog

  52. Ajaykumar Chanda says:


  53. Scarlet Light says:

    I swear to Christ I read this as "The Frog that killed 12,000 people", so when he started talking about "FOG", I was very disappointed…

  54. Mia Firoza says:

    fog =frog ,ha ha ha!

  55. Banagan says:

    This is Chiang Mai today :/ looks like it will take 1000s of instant deaths before they do something about it.

  56. Ismail Abdelirada says:

    "It turns out, turning the air into poison: not a good idea."

    Well, crumbs! There goes our entire economic model.

  57. foompthedroid says:

    I like how they have quit using imperial measurements. Socialists.

  58. Subsetgaming says:

    Also known as the mist.

  59. Sebastian Yu says:

    This kind of environmental problem is one of many massive problems if you don’t regulate corporations

  60. David's Zoo says:

    At first I thought it said frog

  61. matt mostowicz says:

    If you think that was bad then try being stuck in my living room after my vegan wife eats her artificial chopped liver made from kidney beans and spices I can't pronounce. It isn't fog. It's a biblical creeping death. She says it's supposed to be healthy. …. I think she went to college with some lobbyists.

    Lobbyist logic = Well we can have our clean air and still buy our cheap junk because all the crap in the air is in China or India. It's technically not out problem.

    Smelly Vegan Wife Logic = Just go in another room. It doesn't matter that the entire apartment is almost 100% airtight and contaminated. If she doesn't hear me coughing and fighting dry heaves from the other side of the apartment, there isn't a problem.

    Darwin needs a resurrection.

  62. Doge says:

    I thought this was called The frog that killed 12,000 people

  63. Flap Jack Stevens says:

    It wasn't just that they were burning coal. It was the type of coal. Post-war, solid, cleaner coal was used for industry, while homeowners were sold a cheaper coal that was basically dirt with coal in it, which produced a lot more airborne filth when burned.

  64. Brian Cliffdogg says:

    Couldn't the flu have exacerbated an already bad situation?

  65. Biv Lab says:

    New idea for protest at White House/congress coal grills+ fog machines + gaint fan = make them sit in the fruits of their own stupidity on climate change.

  66. Jacqueline Paddock says:

    I remember that smog, it was, thick and smelly and it to follow you in doors. I was kept home from school so we're most of the others in my class.

  67. citizenschallengeYT says:

    You might include a few words about how population growth influenced the smog over the decades and centuries.. (nice shirt)

  68. The Great Dalek Exterminator says:

    I never knew this happened…

  69. Michael Vernon says:

    At the end he said, "you're great" it really hit me. Ty hank

  70. luciusandco says:

    If you've ever been to London, even the "clean" air feels like you're breathing gravy. It's so thick and dirty and I got ill as soon as I went

  71. Patriotic Justice says:

    People: gripe about air pollution.
    People: never say a word about China producing the most pollution in the world.

  72. Twilight Hunter says:

    This is one of the reasons jack the ripper was so much more dangerous

  73. Gary Lewis says:

    im pro nuclear power in part because of hearing the story of the killer smog of 1952. please visit

  74. Noble Hill says:

    What day, was Dec,5 1952

  75. Noble Hill says:

    Human beings are stupid!

  76. 探偵Levi says:

    Green Day

  77. beeble2003 says:

    "London's famously foggy." London isn't foggy at all. It was in the 1950s but what's next? "Alabama's buses are famously segregated"?

  78. Ege Erkut says:

    *Beijing and pretty much all of china “coughs” in the backround*…

  79. Clayton Paisley says:

    Trump is quietly dismantling most of our modern clean air regulations and enforcement in the US. Just thought I'd throw that out there.

  80. kingpest13 says:

    OMG, I read that as F R O G! Embarrassing

  81. Sandy J Renfroe says:

    Their caber is made of Legos.

  82. Lloyd Green says:

    you should look into what killed hundredths of new yorkers in the 60s

  83. SoTyp Me says:

    Wait…trains collided? They relied on seeing each other to avoid collision?

  84. T Klein says:

    The world is a much cleaner place and people are worried about global warming?

  85. Ralf Häggström says:

    What about trumps " CLEAN COAL " ? ? ………………….

  86. Iris lol says:

    US firstly leave world environment protect group cause it will loss $$$, thus our earth pay for it !

  87. Leah Garces says:

    The great smog of London
    The great fire of London
    The great stink of London
    The great of flood of London
    Next: The great ?____? of London


  88. infinitecanadian says:

    The Industrial Revolution started in the mid-1800s, not in the 1700s.

  89. steal threaded says:

    its cool, trump went ahead and got rid of all the regulations so we should be seeing this again soon.

  90. Nicky Nicknick says:

    1:12 well i thought it should be Sulphurous acid, but i also forgot there is oxygen in the air

  91. Raving Rando says:

    Hey China! Take freaking notes!

  92. Bob Jackson says:

    When I was a kid in UK in the 1950's smogs were common. People died every year. We used to call them pea soupers. My mother frequently had to wash clothes several times, also the washing line would be coated in soot. You knew it was a bad one when you couldn't see your own outstretched hand (that isn't a joke). You could really taste the smoke in the air. At that time every house had one or more coal fires and Britain was still a major manufacturing centre, and of course every factory had it's chimney.

  93. Major Bollocks says:

    Industrial Revolution in the 1700's?

  94. Matthew Madruga says:

    Money kills directly this time.

  95. Lisa Lister says:

    Very informative… enjoyed watching.

  96. Utareangara says:

    If you watcht The Crown Season 2, It gets highlighted. its takes up the whole episode

  97. CANALI Rodriguez says:

    Damn you really fooled me. I thought the title said the londons frog that killed 12,000 people. Damn Im waiting to hear about this thing….

  98. voilaviolamh says:

    So many ppl really don't realize how exceptionally blessed they are in all of human history to live in the modern west. Even today, there are areas in China where ppl deal with this same thing, for the most part: intense pollution. We in the west are very comfy and complacent, so much so that many of us have no clue how spectacularly great we have it in comparison with all of human history.

  99. Ian Canuckistan says:

    The smog actually created sulfurous acid, not sulfuric acid. But seeing as most viewers came for the killer frogs it doesn't really matter.

  100. Rob Smith says:

    For some reason i read the frog that killed 12,000

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