Findings of the report:
- Background radiation levels that emitted from natural sources such as rocks, sand or mountains, are nearly three times more than what’s been assumed in Kerala.
- The average natural background levels of gamma radiation in India were 94 nGy/hr (nanoGray per hour) (or roughly 0.8 millisievert/year).
- The last such study, conducted in 1986, computed such radiation to be 89 nGy/hr.
1 Gray is equivalent to 1 Sievert, though one unit refers to radiation emitted and the other to biological exposure.
About the Background Radiation:
- Background radiation levels are emitted from natural sources such as rocks, sand or mountains.
- All rocks and soils contain some trace amount of natural radioactivity and can sometimes be ingested or inhaled if disturbed.
Radon is a gas that can concentrate indoors and be inhaled, along with its decay products.
- Radiation results from the disintegrating nucleus of an unstable element and these can be from anywhere, including from inside our bodies to the constituents of matter.
- Gamma rays are a kind of radiation that can pass unobstructed through matter. Though extremely energetic, they are harmless unless present in large concentrated doses.
- Standard Limit:
- Public exposure shouldn’t exceed 1 milli-Sievert every year; those who work in plants or are by virtue of their occupation shouldn’t be exposed to over 30 milli-Sievert every year.
The International Atomic Energy Agency (IAEA) specifies maximum radiation exposure levels and this has also been adopted by India’s atomic energy establishment.
Source of background radiations:
Natural Source: Natural sources, such as the earth, air, building materials, and food, provide the majority of background radiation. Cosmic rays from outer space also contain radiation.
- Cosmic Rays- Radiations that reach us from outer space
- Animals- All Animals emit a natural level of radiation.
- Rocks- Some rocks give off radioactive radon gas.
- Soil and plants- Radioactive material from the rock is absorbed by the soil and passed to plants.
Artificial Source: Human activity, on the other hand, has increased background radiation by building and employing artificial radiation sources.
- X-Rays- When going through security or having an X-ray in the hospital, we are exposed to this type of radiation.
- Nuclear missile- Man has exploded bombs in the environment, producing radioactivity.
- Nuclear Power- Radiation has been emitted into the atmosphere by nuclear power plants.
Factors affecting Background radiation:
- Background radiation varies from place to place and over time, depending on the amount of naturally-occurring radioactive elements in soil, water and air.
- Weather conditions also affect radiation levels, as snow cover may shield these elements, and radioactive particulates can wash out of the air during rain storms.
- Cosmic radiation from the sun, our galaxy, and beyond is constantly around us and contributes to natural background radiation.
- Altitude and latitude can also influence the level of background radiation at any one site.