# EMF Exposure Metrics & Units: µT, V/m, W/m², SAR Explained > If the unit is wrong, the risk story is wrong—magnetic flux density is not SAR. *Published 2026-07-10 · Updated 2026-07-10 · By Elena Voss* In short **ELF magnetic**: µT (or mG; 1 µT=10 mG). **ELF electric**: V/m. **RF**: W/kg **SAR** (localized/whole-body) and W/m² power density. FCC phone SAR limit **1.6 W/kg (1 g)**. Never cross-compare unlike units. If the unit is wrong, the risk story is wrong—magnetic flux density is not SAR. *This article is informational and editorial only. It is not medical advice, diagnosis, or a treatment plan. Numbers and literature ranges cited here are not personal prescriptions. Consult a qualified clinician before changing medications, supplements, diet, equipment, or management of a diagnosed condition. Seek urgent care for emergencies.* ## Which metrics belong to ELF versus RF? Power-frequency magnetic fields are reported in **microtesla (µT)** or milligauss (mG). Electric fields use **volts per meter (V/m)**. RF near transmitters may use power density (W/m²), while device compliance often uses specific absorption rate (**SAR**) in W/kg averaging mass ([NCI](https://www.cancer.gov/about-cancer/causes-prevention/risk/radiation/electromagnetic-fields-fact-sheet); [ICNIRP LF fact sheet](https://www.icnirp.org/cms/upload/publications/ICNIRPFactSheetLF.pdf)). Unit mapBandMetricUnitNotes ELF-MFMagnetic flux densityµT (1 µT=10 mG)Epidemiology often µT time-weighted ELF-EFElectric fieldV/mEasily shielded by buildings RF deviceSARW/kg1 g (FCC) vs 10 g (ICNIRP) averaging differ RF far-fieldPower densityW/m²Base stations, far-field ## What SAR numbers actually mean on a phone box? SAR estimates the rate RF energy is absorbed in tissue under standardized test positions—not your exact pocket geometry all day. U.S. FCC limit for partial-body is **1.6 W/kg averaged over 1 g** of tissue; ICNIRP uses different averaging (often 10 g) and limit values in its 2020 RF guidelines ([FCC SAR](https://www.fcc.gov/general/cell-phones-and-specific-absorption-rate); [47 CFR 1.1310](https://www.law.cornell.edu/cfr/text/47/1.1310); [ICNIRP 2020](https://www.icnirp.org/cms/upload/publications/ICNIRPrfgdl2020.pdf)). Lower SAR among compliant phones is not a clinical outcome ranking. ## How do time-averaging and spatial averaging trick readers? ELF epidemiology often uses time-weighted average magnetic fields in homes. Spot peaks near appliances can be high for seconds without matching the chronic average linked in studies. RF SAR tests use specified distances; real-world body contact and network power control change absorption. Report averaging windows with the number. ## What conversion and comparison anti-patterns fail? Converting phone SAR to power-line µT; treating mG and µT as identical without the 10× factor; quoting instantaneous peaks as chronic means; ignoring 1 g versus 10 g SAR averaging when comparing U.S. and international limits ([ICNIRP RF page](https://www.icnirp.org/en/frequencies/radiofrequency/rf-emf-100-khz-300-ghz.html)). Unit discipline is the cheapest high-impact risk-communication upgrade. ## What practical reading rules should you keep when scanning this topic? Health Canon treats contested exposure and immune topics with a fixed editorial stack: name the mechanism or chemical, state the units, separate ecological from human clinical risk when the dose bridge fails, and prefer primary agency or society sources over secondary slogans. For **EMF Exposure Metrics & Units: µT, V/m, W/m², SAR Explained**, that means reading every number with its matrix (serum versus finished water versus effluent; outdoor PM versus indoor allergen), its time window (acute minutes versus chronic months), and its evidence grade. Guidelines and monographs set the floor; blogs do not. Sexual dimorphism, age, pregnancy, and occupational exposure can move priors without rewriting mechanism. When two literatures collide—for example fish vitellogenin at nanograms-per-liter versus human contraceptive micrograms—keep both true by refusing false equivalence. Mitigation hierarchy always prefers source control and validated medical or engineering therapy over gadget stacking. If a claim cannot survive a unit check and a study-design check, it does not belong in a decision table. Update your mental model when major agencies re-evaluate (IARC, NCI, WHO, EPA, GINA, AAAAI, EAACI, ICNIRP) rather than when a single preprint trends. This page is orientation content for literate adults; it does not replace an allergist, toxicologist, occupational physician, or water-utility engineer when your case is high-stakes. Re-read the sources table and re-verify URLs before citing any figure in professional work. Local regulation, product labels, and clinical guidelines supersede general editorial synthesis whenever they conflict. Cross-link mental models across the network: allergy is not the same as systemic low-grade inflammation; EE2 ecological risk is not a contraceptive pill dose in tap water; RF heating limits are not a verdict on every non-thermal claim. Those separations are the product of the research dossier behind this article (*exposure-metrics-units*), not marketing copy. When you share numbers, include the citation year and the matrix so others cannot launder effluent data into kitchen-tap panic or laboratory SAR into bedroom Wi-Fi mythology. That discipline is how long-form environmental and immune health writing stays useful under SEO pressure without sacrificing accuracy. Editorial continuity for *exposure-metrics-units*: restate load-bearing quantities from the research dossier, preserve outbound HTTPS citations, and refuse placeholder prose. Readers who only skim headings should still leave with a unit-aware model, a diagnostic or exposure hierarchy, and a clear list of anti-patterns. Numbers without methods are marketing; methods without numbers are incomplete. Keep both. Editorial continuity for *exposure-metrics-units*: restate load-bearing quantities from the research dossier, preserve outbound HTTPS citations, and refuse placeholder prose. Readers who only skim headings should still leave with a unit-aware model, a diagnostic or exposure hierarchy, and a clear list of anti-patterns. Numbers without methods are marketing; methods without numbers are incomplete. Keep both. ## Sources 1. [ICNIRP RF guidelines 2020](https://www.icnirp.org/cms/upload/publications/ICNIRPrfgdl2020.pdf) 2. [FCC SAR overview](https://www.fcc.gov/general/cell-phones-and-specific-absorption-rate) 3. [FCC exposure limits CFR](https://www.law.cornell.edu/cfr/text/47/1.1310) 4. [ICNIRP low-frequency fact sheet](https://www.icnirp.org/cms/upload/publications/ICNIRPFactSheetLF.pdf) 5. [NCI EMF metrics context](https://www.cancer.gov/about-cancer/causes-prevention/risk/radiation/electromagnetic-fields-fact-sheet) --- Source: https://healthcanon.com/environmental-health/exposure-metrics-units Index: https://healthcanon.com/llms.txt · Full text: https://healthcanon.com/llms-full.txt