Radiation is all around us

Radiation is all around us
This might surprise you, but the fact is that all of us are surrounded by natural radiation, no matter where we live on the earth. This naturally omnipresent radiation is called the background radiation. The most obvious and directly visible source of radiation is the sun, which bombards us continuously with radiation. The earth is also showered with cosmic rays day and night.
Also, when we fly high in jet airplanes, at those high altitudes the atmosphere is thinner and we receive far more radiation than when you are at sea level. Typically, a flight passenger receives 1 millirem of radiation dose for every 1,600 km of air travel. In the same manner, not only flying in planes, but also living at high altitudes causes you to receive greater dosages of natural radiation. Even at moderate altitudes of 4,000 to 6,000 ft., a person typically receives an annual dose of 21 to 29 millirems each year. At 8,000 to 9,000 ft. above mean sea level, the natural radiation doses increase to 70 millirems annually. People living higher up in the mountains are exposed to even greater doses of natural radiation.
The surface of the earth itself emits radiation constantly all around the globe. So there is no way to escape from natural radiation. Indeed, there is no place on the earth where radiation does not exist. This radiation comes from the natural spontaneous disintegration (radioactivity) of radioactive isotopes of elements such as uranium and thorium found in sea water as well as the soil and rocks of the earth. Radon, a radioactive gas, is one of the products of this natural radioactivity. Since radon is emitted from soil, bricks and rocks, the walls of homes and offices emit radon. No wonder, radon is a universal source of terrestrial natural radiation doses. In fact, it is the major source of daily radiation exposure to humans. About 55 per cent of background radiation comes from the radioisotope Radon-222 and its daughter products. One could expect to receive an average of 7 millirems of radiation dose annually simply by living and working in buildings. Construction materials such as cement, stone, brick, sand, granite, clay, fly ash, lime stone, gypsum etc. are all naturally radioactive to varying degrees. Here also, if you have used materials like marble and granite to decorate your place, then you are subjected to higher doses of radiation, because these are more radioactive than other building materials. Now let us consider an example to illustrate this point. The Grand Central Station of New York gives you relatively high levels of radiation doses due to the granite that has been used lavishly in its construction. While the commuters take their daily trips to their offices and back from this station, not many of them know about this fact, and are neither affected adversely. The fact is that rocks of all sorts contain trace amounts of radioactivity, but granite has it more compared to others. Another such famous example is that of the ‘United States Capitol Building’ – the American equivalent of the Indian Parliament Building (Sansad Bhavan). The US Capital Building is at least 55 times more radioactive than the permissible limits by modern standards, because of the heavy use of granite. And despite this relatively excessive radiation, there have been no observable ill-effects of radiation on people.
Natural background radiation levels vary from place to place. At some places on the earth, extremely high levels of natural background radiation exist. Take the example of Ramsar in northern Iran. This is the most radioactive inhabited place on the earth. Here the radiation levels are up to 260 millisieverts (mSv), that is, 260,000 microsieverts. Now compare this to the average background radiation level on the earth, which is about 2.4 mSv. If you knew about the extremely high radiation levels existing in Ramsar, you would be scared to live there. But even under such high radiations levels, people have lived there for generations without any observable adverse effects of radiation. Even some parts in Kerala in India, there are regions where high levels of natural radioactivity exists due to high radioactivity of thorium-bearing rocks and soil. Here too people live without being affected by radiation in any abnormal way.
If you are surprised to know all these facts, then here is some more surprise for you. Human bodies themselves are radioactive. This radioactivity comes from the food we eat, the water we drink and the air we breathe. Yes, food, water and air contain naturally radioactive substances. Thus, human body contains radioactive isotopes like Tritium, Carbon-14 and Potassium-40, Radium-226, 228 and Thorium-228. Vegetables, pulses, fish, rice, milk – all of them contain radioactive substances.
Radiation has existed for as long as the universe has existed. On the earth, living creatures have evolved to learn to live and thrive amid radiation. Life on earth began to flourish amid radiation levels that were much higher than they are present today. Over these long geological periods, there has been a substantial reduction in natural background radiation, as significant amounts of radioactive isotopes and their radioactive products have decayed away ever since. So, we live on a much less radioactive earth today.
Beyond natural radiation, we are exposed to manmade radiation. For example, we are also routinely exposed to radiation from airport baggage scanners, fire detectors, etc. in our daily lives without any harm. Medical diagnostic procedures give us much higher radiation doses. You get more radiation in just a fraction of a second from a single medical X-ray than by living near a nuclear power plant for years. For example, just one ‘dental’ X-ray exposes us to radiation doses equivalent to those received by living at the boundary of a nuclear power plant for ten years. Radiation doses from a chest X-ray are even higher. A single CT scan gives many times more radiation doses than even an X-ray examination. Compared to this, the fact is that the radiation dosages due to the operation of a nuclear power plants are extremely small, negligible and within internationally prescribed limits.
Radiation is a life saver in cancer treatment. High-intensity gamma radiation kills cancer cell. Radiopharmaceuticals are another route for cancer treatment. Plutonium powers the pace makers that are used for saving the lives of heart patients. Radiation is also used in various industries, biomedical research, for invention and testing of pharmaceuticals, as well as in many machines that make a host of consumer products. What’s more, small fission reactors using nuclear fuel are employed as power source in spacecraft. Small nuclear reactor powers nuclear submarines as well as icebreaker ships that travel through the polar marine routes.
Inadequate and unreliable information can cause misconceptions and unrealistic apprehensions about radiation. On the other hand, looking at radiation in the light of vital scientific facts can provide us a rational point of view.