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How Much Radioactivity will Kill You?


The word “radiation” hits us as something formidable almost instantly. We are quite aware of what radiation could do to us – it creates mutations that are largely detrimental (yes, we are not going to become superheroes) and can lead to lifelong complications.


Radiation exists everywhere – from the air we breathe to the light we see. However only high energetic rays like gamma rays, X-rays and UV rays are harmful to us. These are named ionizing radiation as they tend to rip electrons off atoms ionizing them. Ionizing radiation is one of the leading causes of cancer as it damages our genetic material. However, we are not aware of how different sources of radiation affect living beings.


The Discoverer’s Fate


Polish born Madam Marie Skłodowska discovered radioactivity in 1898 along with her colleague and husband, Pierre Curie. She was inspired by Henri Becquerel who in 1896 observed that Uranium emitted mysterious rays that can react with photographic film. Marie observed that Thorium too had this property. She figured that the strength of radiation was dependent only on the amount of substance taken suggesting that radioactivity was fundamental to these atoms. This was also hinting at atoms not being indivisible in nature. In 1898, she and her husband discovered Polonium – named after Poland – and Radium – latin for ray.


In 1903, the Nobel Prize in Physics was given to Pierre Curie, Marie Curie and Henri Becquerel making Marie Curie the first woman ever to win a Nobel Prize. She also won a Nobel Prize in chemistry later in 1911. Her work has led to so many advancements in the fields of nuclear physics, chemistry and medicine. Curie died in 1934 because of a bone marrow disease that people suspect to have been caused by prolonged exposure to radioactive substances. Her remains are still radioactive and are kept in a lead-lined coffin.


Banana Units


The radioactive strength of a material is measured in sieverts. Typically, 2 sieverts of radiation at once can kill a human being. Bananas are a good way to measure radioactivity too since the potassium in them give off 0.1 microsieverts of radiation – 20 million bananas could kill you. People around the world experience around 2400 microsieverts of radiation every year – 24,000 bananas – due to the radon in the air, cosmic radiation from space, food, water and medicines. Taking a flight however will expose you to 3 microsieverts every hour. Worse than that is living around Chernobyl – the place where the most catastrophic nuclear accident took place. There is a background radiation of around 7 microsieverts every hour and living around Fukushima, the recently affected nuclear zone, exposes you to 10.3 microsieverts (103 bananas) every hour.


Comparatively hospitals expose you to very high levels of radiation. A CT scan taken on your abdomen exposes you to 10,000 microsieverts (100,000 bananas) at once which is around four times the amount of background radiation an average human receives every year. What’s worse however is going to outer space since there won’t be an atmosphere to protect you. Astronauts receive around 80,000 microsieverts in the six month trip they take to outer space. However none of this triumph smoking.




An average smoker’s lungs see around 160,000 microsieverts – 1.6 million bananas – of radiation every year. The fertilizers farmers use to increase the size of tobacco crops contain radium that decays into radon, lead-210 and polonium-210. The lead-210 and polonium-210 atoms emit alpha and gamma radiation. These atoms settle in a smoker’s lungs building up over years. They can damage the lungs and can cause lung cancer.


Around 14% of children below the age of 16 still use tobacco in India and over 1 million people die from smoking every year in the country. In the United States, there are more deaths caused by smoking than alcohol, aids, car accidents, homicides, illegal drugs and suicides – combined. Even interacting with a smoker is dangerous since smokers themselves are sources of high levels of radiation.


As shocking as this may seem, we are all surrounded by one smoker or the other all the time and are exposed to high levels of radiation. Could this prove to be a reason to quit smoking?

Sources: Veritasium, Ted