Radiation comes in two forms, Ionizing and Non-ionizing. Ionizing radiation removes electrons from atoms and molecules of materials that can include air, water, and living tissue. Examples of Ionizing radiation are X-rays, Gamma rays, and also alpha, beta, and gamma rays from radioactive decay.
Non-ionizing radiation differs from ionizing radiation in the way it acts on materials. Unlike x-rays and other forms of ionizing radiation, non-ionizing radiation does not have enough energy to remove electrons from atoms and molecules. They do have the ability to heat substances. Non-ionizing radiation can include radiofrequency, microwaves, and infrared radiation.
Radiation can interact with DNA directly and cause damage by breaking bonds in the DNA or indirectly by breaking water molecules surrounding the DNA. When these water molecules are broken, they produce free radicals, which are unstable oxygen molecules that can damage cells and organs.
Once a cell is damaged, three things can happen;
Every day we are exposed to radiation in some form, from natural sources (e.g. cosmic radiation, solar radiation, terrestrial radiation) and manmade sources (e.g. X-rays, Computed Tomography (CT) scans, Positron Emission Topography (PET) scans). These sources of radiation are at very low doses and are unlikely to cause harm. It is possible for the increased likelihood of problems to develop over time in some circumstances, such as excessive Ultraviolet exposure causing skin cancer, or living in an area with high Radon levels (a natural radioactive gas) causing lung cancer.
In the CBRN context, the risk is where deliberate exposure of high levels of radiation is used with the intent to cause harm. This could be done in 2 forms:
Use of radioactive decay:
Radioactive decay is the process in which a radioactive atom spontaneously gives off radiation in the form of energy or particles to reach a more stable state. There are 4 types of radiation given off:
Within a terrorism context, food and drink products could be poisoned with alpha or beta particles, causing harm to individuals who consume them. Using Gamma or Neutron emitting particles could cause harm to people within the vicinity of the radioactive material emission.