Glossary

Italy's two precautionary legal tiers below the exposure limit: the attention value applies where people spend four or more hours a day, the quality objective applies outdoors in busy areas.

Regulatory limits apply to an average: 30 minutes for the general public under FCC and ICNIRP rules, 6 minutes for occupational exposure.

5G massive-MIMO antennas steer energy toward active users rather than radiating uniformly, so exposure is intermittent and direction-dependent.

A German-origin discipline whose SBM testing methodology grades sleeping areas into precautionary bands far below regulatory limits.

High-frequency harmonics and transients riding on mains wiring, typically from dimmers, switch-mode supplies and inverters. Not a term used in any exposure standard.

The fraction of time a transmitter is actually radiating — the reason a peak reading and a time-averaged exposure can differ by a factor of a hundred or more.

Symptoms attributed by the affected person to EMF exposure; recognised as real symptoms by WHO, without a demonstrated causal link to field exposure in blinded studies.

Transmitter power multiplied by antenna gain: the figure that, with distance, determines free-space power density.

Fields below about 300 Hz, dominated by the 50 or 60 Hz power supply and its harmonics.

Beyond roughly a wavelength from an antenna the field behaves as a propagating wave and inverse-square estimates apply; closer than that they do not.

A continuous grounded conductive enclosure. Effective in principle, and in practice limited entirely by its apertures.

'Possibly carcinogenic to humans' — a statement about how strong the evidence is, not about how large any risk is.

A precautionary legal limit applied to a single installation at sensitive locations, used in Switzerland and set far below the general exposure limit.

In the far field, doubling the distance quarters the power density: the cheapest and most reliable mitigation available.

The two units for power-frequency magnetic fields: 1 µT = 10 mG, so 0.4 µT = 4 mG.

The FCC's term for the enforceable exposure limit expressed as field strength or power density.

When the current flowing out on a circuit does not return on the same cable, the imbalance radiates a magnetic field across the whole building.

Electromagnetic radiation whose photons lack the energy to remove electrons from atoms — everything below ultraviolet, including all EMF discussed on this site.

A proposed biological effect at exposure levels too low to cause measurable heating; the central claim of precautionary guidelines and the central objection of regulators.

The basis for values set below the level justified by established effects, such as the Swiss installation limits and building-biology bands.

ICNIRP's two-tier structure: basic restrictions are the dosimetric limits that matter biologically; reference levels are the externally measurable proxies derived from them.

Fields from about 100 kHz to 300 GHz, the range used by all wireless communication.

Watts absorbed per kilogram of tissue, the dosimetric basis of phone compliance testing — 1.6 W/kg over 1 g in the U.S., 2 W/kg over 10 g under ICNIRP.

Attenuation expressed logarithmically: 10 dB removes 90% of power density, 20 dB removes 99%, 30 dB removes 99.9%.

Tissue heating from absorbed RF energy — the established mechanism that RF exposure limits are set to prevent, with a safety margin.

The North American equivalent of the general-public and occupational tiers: 'uncontrolled' means people who are not aware of their exposure and cannot act on it.

Three units for the same RF quantity, spanning ten orders of magnitude: 1 mW/cm² = 10 W/m² = 10,000 mW/m² = 10,000,000 µW/m².