Safety standards for human exposure to radio frequency radiation and their biological rationale

Exposure guidelines for RF radiation have been promulgated for nearly half a century. However, our understanding of biological effects of exposure to RF radiation is still evolving and more so for cellular mobile telephones and wireless personal communication devices. There are two different sets of guidelines promulgated for limiting human exposure to RF radiation, worldwide. Currently, there is a backdrop of persistent, publicly expressed lack of confidence in radio-frequency (RF) exposure standards, pertaining to the maximum permissible exposure (MPE) level of humans exposed to RF electromagnetic radiation. Much of the current effort is driven by the advent of cellular mobile telephony, which uses RF radiation in the range of 800-2,500 MHz. The setting of guidelines or standards for maximum permissible levels of exposure to RF and microwave radiation is a valid approach to managing the risk of such exposures. The existing guidelines, however, are based on results obtained from acute, short-term studies that are atypical of the RF exposures associated with the handset of cellular mobile telephones. For the first time in human history, a source of RF radiation is located right next to the head of millions of cellular mobile telephone users. Biological effects after repeated, prolonged, or lifelong exposure to RF energy emitted by these low-power wireless telecommunication devices have been investigated only during the past few years. The existing scientific results are equivocal and arguable in many respects. Consequently, there remains a widespread public concern about the adequacy of existing guidelines in safeguarding the general population against possible harm of RF radiation from cellular mobile telephones.