Australians are exposed to radiation from a variety of natural (background) and artificial sources. Radiation is energy traveling as waves or particles, and can be divided into two classes:
- Ionising radiation
- Non-ionising radiation.
Ionising radiation (IR) has enough energy to change the chemical composition of matter. It is produced by X-ray machines and radioactive decay from natural and artificial radioactive materials.
Naturally occurring IR is present in the environment due to radioactive minerals remaining from the very early formation of the Earth. This leads to exposure to gamma rays and radioactive radon gas from certain rocks and from radioactive material in our food and drink.
We are also exposed to cosmic IR that comes from outer space (eg the sun) and passes through the atmosphere to Earth.
There are three main sources of artificial IR. They are from:
- medical uses including diagnosis of many diseases and treatment of cancer
- industrial uses, mainly in measurement and scientific research
- fallout from nuclear weapons testing and accidents around the world.
Some common consumer products that may contain IR radioactive materials, or which may increase your annual exposure include:
- smoke detectors
- gas lantern mantles
- air travel
- living at high altitude
- radon in homes
Non-ionising radiation (NIR) has less energy but can still excite molecules and atoms, causing them to vibrate faster.
Naturally occurring NIR exists in the form of solar ultraviolet (UV) radiation, but most NIR comes from many modern technologies such as:
This kind of NIR is often referred to as electromagnetic radiation.
Generally, IR is considered more hazardous than NIR due to the high energies and penetrating power which is released from the radioactive material.
We cannot eliminate radiation from our environment, but by having a good understanding of radiation and controlling our exposure, we can reduce our risk.