Sources of ionizing radiation exposure

Until recently, the radiations to which people were exposed were limited to those that exist naturally. But beginning about a century ago a number of advances in science and engineering altered our radiation environment. The use of X rays, radioactive substances, artificial illumination, and radio communication; the high voltage transmission of electric energy; and even the introduction of high-flying aircraft have all affected the kinds and amounts of radiation to which people are exposed. This article will discuss only the ionizing radiations, which are those produced by X-ray machines and radionuclides. 22 references