2Radiation is everywhere CosmicInhaled RadonBodiesPlantsRadioactive ElementsRocksWe live in a sea of radiation…
3BACKGROUND RADIATIONThe average background radiation per person is 370 millirems (mrem) per year. This varies widely depending on where someone lives, and their occupation, health and lifestyle.
4Background RadiationMost background radiation is natural. It is part of nature. It has always been here. People have always lived with it.
5Radiation comes from space- sun and cosmic rays Because this type of radiation is somewhat shielded by the atmosphere, the dose is higher at higher altitudes
6Background Radiation Exposure at Different Elevations -282 Ft427 Ft5,280 Ft10,157 FtEvery 200 feet increase in altitude increases dose 1 mrem/yearEvery 800 feet increase in altitude increases dose 4 mrem/year
7Radiation comes from the earth Radiation comes from the earth Some rocks, like Uranium are radioactive. So are coal and some building materials such as granite.The natural radiation from the granite in Grand Central Station is higher than is allowed to certify a nuclear power plant.
8Radon is a radioactive gas that comes from inside the earth Usually radon escapes into the air in very small amounts and does not hurt us. However, sometimes radon can get trapped in buildings. Then there is more radiation than is healthy for us.
10Cells in our body contain radioactive elements, such as Potassium, which come from the food we eat Milk
11Background RadiationRadioactive elements in our bodies
12Man-made Background Radiation Other radiation is man-made. Radiation from X-rays, medical isotopes, televisions, smoke detectors, nuclear fuel, and weapons fallout are all man-made sources of radiation.
13Normal annual exposure from natural radiation About 300 mrem/yrRadon gas mremHuman body mremRocks, soil mremCosmic rays mremNormal annual exposure from man-made radiationAbout 70 mrem/yrMedical procedures mremsConsumer products mremsOne coast to coast airplane flight mremsWatching color TV mremSleeping with another person mremWeapons test fallout less that 1 mremNuclear industry less than 1 mremThis slide demonstrates that we all receive a total of about 370 mrem (0.37 mSv) of radiation exposure each year from background sources. The range of exposures from background is very high in different environments. Background radiation increases as a function of elevation, as a function of radon in homes and from natural radioactive materials in the environments. There are some areas where the natural background radiation dose is increased by more than a factor of ten. Many of the man made exposure are being regulated at levels much below background. For example there are some very vigorous discussions on whether the level for exposure from man-made sources should be 15 or 25 mrem per year. Since both of these levels are far below the background level, and the range of background level is so high, it is difficult to justify the needed expense required to comply with the lower standard.
14Background RadiationThe body does not distinguish between natural and man-made. Neither natural nor man-made background radiation has been shown to be harmful. The body has developed repair mechanisms to deal with negative effects of background radiation.