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The FCC limits for maximum permissible workplace exposure to shortwave radio frequency energy in the range of 3–30 MHz has a plane-wave equivalent power density of (900/ f 2) mW/cm 2 where f is the frequency in MHz, and 100 mW/cm 2 from 0.3 to 3.0 MHz.
The antennas contained in mobile phones, including smartphones, emit radiofrequency (RF) radiation (non-ionizing "radio waves" such as microwaves); the parts of the head or body nearest to the antenna can absorb this energy and convert it to heat or to synchronised molecular vibrations (the term 'heat', properly applies only to disordered molecular motion).
Specific energy absorption rate (SAR) averaged over the whole body or over parts of the body, is defined as the rate at which energy is absorbed per unit mass of body tissue and is expressed in watts per kilogram (W/kg). Whole body SAR is a widely accepted measure for relating adverse thermal effects to RF exposure. [9]
English: Radiation Dose Chart by Randall Munroe as part of the webcomic xkcd (SVG version of ). In response to concerns about the radioactivity released by the Fukushima Daiichi nuclear disaster:Fukushima Daiichi nuclear disaster in 2011, and to remedy what he described as "confusing" reporting on radiation levels in the media, Munroe created a chart of comparative radiation exposure levels.
Within these situations, limits are given for certain exposed groups; [10] Planned exposure – limits given for occupational, medical and public exposure. The occupational exposure limit of effective dose is 20 mSv per year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. The public exposure limit is 1 mSv in a ...
Recognized effects of higher acute radiation doses are described in more detail in the article on radiation poisoning.Although the International System of Units (SI) defines the sievert (Sv) as the unit of radiation dose equivalent, chronic radiation levels and standards are still often given in units of millirems (mrem), where 1 mrem equals 1/1,000 of a rem and 1 rem equals 0.01 Sv.
Usually, the alarm of most RF personal monitors is triggered by instant values, however, standard limits are specified as time-averaged values. Some RF monitors have the possibility to trigger alarms based on average values, which is a better indication of the real exposure situation (as an example, an instant value can be at 200% while the ...