There is no escaping radiation anywhere, no matter the location

It may come as a surprise to know that human kind is perpetually surrounded by natural radiation, no matter where they live.

This naturally omnipresent presence is called background radiation. Sun, which exposes us continuously to radiation, is the most prominent source. The earth is also showered with cosmic rays mainly originating outside the solar system. 

When we fly high in jet airplanes, the atmosphere is thinner and we receive much more radiation than at sea level. Living at high altitudes cause increased exposure due to cosmic radiation. 

The surface of the earth constantly emits radiation, so there is no way to escape natural radiation. 

Radon, a radioactive gas, is one of the products of this natural radioactivity. Since it is emitted from soil, bricks and rocks, the walls of homes and offices too emit radon.

Radon, therefore, is a universal source of terrestrial natural radiation dose. 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. 

Construction material such as cement, stone, brick, sand, granite, clay, fly ash, lime stone, gypsum and others, are all naturally radioactive to varying degrees. 

Here too, the use of marble and granite for decoration, subjects people to higher doses of radiation because these are more radioactive than other building materials. 

Railway stations deliver relatively high levels of radiation doses due to the granite used in its construction. Daily commuters, who use this station, are not aware of this fact - naturally, they are not affected adversely. 

Natural background radiation levels vary from place to place. Take the example of Ramsar in north Iran, the most radioactive- inhabited place on the earth. 

People here receive an annual radiation- absorbed dose from background radiation up to 260 millisieverts (mSv). In comparison, the average background radiation level on earth is pegged at about 2.4 mSv! 

Knowledge about the extremely high radiation levels in Ramsar should make it a scary proposition for its residents, but people have lived here for generations without any observable adverse effects. Why, in some parts in Kerala, there are high levels of natural radioactivity due to thorium-bearing rocks and soil. Here too, life remains normal and unaffected.

As a matter of fact, human bodies are themselves radioactive. This radioactivity comes from the food we eat, the water we drink and the air we breathe. Indeed, food, water and air contain naturally radioactive substances. 

Thus, human body contains radioactive isotopes like Carbon-14 and Potassium-40, Radium-226, 228 and Thorium-228. Vegetables, pulses, fish, rice, milk – all contain radioactive substances.

Radiation has existed for as long as the universe. On earth, living creatures have evolved to learn, live and thrive amid radiation.

Interestingly, 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 products have decayed. 

Beyond natural radiation, we are exposed to the manmade variety. Passengers are routinely exposed to radiation from airport baggage scanners, fire detectors and the rest in our daily lives, without any harm. 

Medical diagnostic procedures give us very high radiation doses. It is easy to 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. Just a single ‘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, radiation dosages from nuclear power plants are negligible and within internationally prescribed limits. 

Radiation is a life saver in cancer treatment. High-intensity gamma radiation kills cancer cells. It is also used in various industries, biomedical research, for invention and testing of pharmaceuticals, as well as in machines that manufacture consumer products. 

Inadequate and unreliable information can cause misconceptions and unrealistic apprehensions about radiation. 

Author is Advisor, Nuclear Power Corporation of India Ltd