Power-Frequency Magnetic Field Exposure near Transmission Infrastructure in Taif, Saudi Arabia: Empirical Decay Modeling and Benchmarking Against ICNIRP and EU Precautionary Limits

Rapid urbanization in Taif City, Saudi Arabia, has brought high-voltage overhead and underground power lines into close proximity to residential neighborhoods and recreational areas, yet the Kingdom has no dedicated national standard for public exposure to power-frequency magnetic fields. (1) Background: This study quantified extremely low-frequency (ELF, 50 Hz) magnetic field exposure at eight sites in Taif and benchmarked it against international guidelines and comparable field studies. (2) Methods: The magnetic flux density was measured with two independently calibrated meters (MESTEK EMF01, WINTACT WT3121) at controlled distances from each source over multiple days; the data were analyzed by two-sample t-tests, log–log regression of the spatial decay, and hazard quotient benchmarking. (3) Results: The peak flux density reached 42.5 µT at 0 m from an underground cable, and decayed to below 1 µT within 10–50 m of overhead lines; the fitted decay model B(r) = 3431·r−2.94 (R2 = 0.826) was steeper than the ideal single-conductor law, consistent with three-phase cancellation. All values remained below the ICNIRP 100–200 µT reference level, but several exceeded the 3–10 µT precautionary values applied in the EU, and all exceeded, at close range, the ≈0.3–0.4 µT threshold linked to elevated childhood leukemia risk. The results agree with European (Gajšek et al.), Italian regulatory (Filosa and Lopresto), and Mexican (Ciudad Juárez) field data. All near-source readings also exceeded the EUROPAEM 2016 precautionary guidance values for sensitive populations. Repeat sampling at the overhead line site showed a reproducible diurnal load effect, with midday fields ~28% above morning values and a 1.40 ratio between the largest and smallest readings, confirming that spot measurements cannot represent the 24 h exposure. (4) Conclusions: The findings support a precautionary national exposure framework that treats the ICNIRP reference levels as a ceiling against acute effects rather than as a sufficient standard, and incorporates long-term precautionary values together with targeted engineering mitigation for Taif. Because the reported values are spot rather than 24 h measurements, the exceedances identify sites requiring continuous monitoring rather than confirming regulatory breaches; a 24 h, multi-height, harmonic-resolved campaign is planned as the necessary next step.