Review Article
Sofia Kottou, Dimitrios Nik
Abstract
The natural electromagnetic environment originates from the Earth (terrestrial sources) and from space (extraterrestrial sources). Compared with man-made fields, natural fields are extremely small, especially at the radiofrequency band. Electric and magnetic fields exist wherever electricity is generated, transmitted or distributed from power stations or used in electrical appliances. Since the use of electricity is an integral part of modern lifestyle, these fields are ubiquitous in the environment. The situation became ‘heavier’ with the impressive evolution of the mobile phone and telecommunication technology. The incident fields interact or couple with the human body and induce electric and magnetic fields and currents within the body tissues. Oscillating charges may be induced on the surface of the exposed body and these induce currents inside the body. A different interaction mechanism exists for the electric- and magnetic-field components. Dosimetry describes the relationship between the external fields and the induced electric field and current density in the body and the outcome serves as the basis on which authorities recommend limits for human exposure. The locally induced electric field and current density are of particular interest because they relate to the stimulation of excitable tissue such as nerve and muscle. The distribution of induced currents across the various organs and tissues is determined by the conductivity of those tissues. Many mechanisms, mainly when concerning thermal effects, become detectable only at fields above certain strength. Nevertheless, the lack of identified admissible mechanisms does not rule out the possibility of adverse health effects even at very low field levels, provided basic scientific principles are adhered to