6.4.1 General Public Exposure
The general public includes people of all ages and health conditions who may have little knowledge of, or control over, the RF fields to which they are exposed. They may not even be aware that such fields exist. General-public exposure can occur through the intentional use of transmitting equipment, through the operation of domestic and consumer devices, or through fields produced by installations in the surrounding environment.
Personal exposure is commonly dominated by devices used close to the body. Examples include mobile phones, cordless telephones, Bluetooth headsets, body-worn radios, wireless computers, and other connected equipment. Although these devices usually have modest transmitter powers, their proximity to the user can produce greater localized exposure than much more powerful transmitters situated at considerable distances. The operating mode is also important: a mobile phone transferring data under poor coverage conditions may transmit more frequently and at a higher power than the same phone in standby mode or operating close to a base station.
Environmental exposure arises from sources that are not being personally operated by the exposed individual. Examples include radio and television broadcasting stations, mobile-network base stations, fixed microwave links, satellite earth stations, radar installations, and wireless access points. These sources may have substantially greater transmitter powers than personal devices, but their antennas are generally separated from publicly accessible areas. Exposure at a particular location depends on antenna height, orientation, gain, beam shape, transmitted traffic, terrain, buildings, and distance. Multiple sources and frequencies may contribute simultaneously to the total exposure.
Domestic appliances can create additional localized fields. Microwave ovens, induction cooktops, wireless charging systems, smart devices, and security or identification systems all produce fields with very different frequencies, spatial distributions, and operating cycles. For enclosed appliances, such as microwave ovens, external exposure is governed principally by leakage rather than by the power delivered inside the appliance.