ABSTRACT
Radiofrequency (RF) electromagnetic waves originate from charged particles and propagate through space in a wave-like behavior. The electrical and the magnetic components are orthogonal to each other with a fixed ratio of intensity. The propagation pattern depends on the type of source and the type of dispersion. For a point source with nondirectional dispersion, the electromagnetic field (EMF) level decreases with the square of distance from the source (~1/r²). For a point source with directional dispersion, the EMF level decreases inversely with the distance from the source (~1/r). In practice, however, the propagation pattern may be more complex. Fixed site transmitters such as broadcasting or mobile phone antennae may be characterized by a mixture of directional and nondirectional propagation producing a decrease that is between 1/r and 1/r². The EMF at a given location (i.e., receptor) can thus be calculated from the antennae emission characteristics and the geometry between the source and the receptor point. Physical characteristics of the environment and potential reflections, however, can make this calculation quite
CONTENTS
Radiofrequency Electromagnetic Fields: Characteristics and Typical Sources .................. 125 Reference Values for RF-EMF .................................................................................................... 128 Near-Field and Far-Field RF-EMF Sources.............................................................................. 128 Assessment of Exposure to RF-EMF Sources for Epidemiological Purposes .................... 129
Far-Field RF-EMF Sources .................................................................................................... 130 Distance to the Closest Fixed Transmitter...................................................................... 130 Spot Measurements in Bedroom (Stationary Devices) ................................................. 130 Personal Measurements with Exposimeters .................................................................. 130 Geospatial Propagation Models ...................................................................................... 132 Exposure Prediction Models ............................................................................................ 132
Near-Field RF-EMF Sources ................................................................................................. 133 Exposure Distribution in the Population ................................................................................. 134
Far-Field RF-EMF Sources .................................................................................................... 134 Near-Field RF-EMF Sources ................................................................................................. 134 Combination of Near-and Far-Field RF-EMF Exposure .................................................. 136
References ..................................................................................................................................... 137
complex, in particular if the receptor is not in the line of sight of the source (e.g., shielded by topography or buildings).
