Maps and driving instructions for evacuation and temporary shelter. The nature of contamination. Each of us is exposed to some radiation every moment of our lives from radioactive materials all around us. The sun covers the earth with cosmic radiation. Some rocks and minerals give off small amounts of radiation, such as radon gas.
Radioactive particles are in the air and in our food and water.
Many building materials also contain radiation. Even our bodies are mildly radioactive. All together, radiation from these sources is called natural background radiation. Human-made radiation Ionizing radiation also comes from human sources. It is used in the medical field to diagnose and treat disease.