Children and adults exposed to electromagnetic fields at the ICNIRP reference levels: theoretical assessment of the induced peak temperature increase.

Abstract

To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels. Restrictions on induced whole-body-averaged specific absorption rate (SAR(wb)) are provided to keep the whole-body temperature increase (T(body, incr)) under 1 °C during 30 min. Additional restrictions on the peak 10 g spatial-averaged SAR (SAR(10g)) are provided to prevent excessive localized tissue heating. The objective of this study is to assess the localized peak temperature increase (T(incr, max)) in children upon exposure at the reference levels. Finite-difference time-domain modeling was used to calculate T(incr, max) in six children and two adults exposed to orthogonal plane-wave configurations. We performed a sensitivity study and Monte Carlo analysis to assess the uncertainty of the results. Considering the uncertainties in the model parameters, we found that a peak temperature increase as high as 1 °C can occur for worst-case scenarios at the ICNIRP reference levels. Since the guidelines are deduced from temperature increase, we used T(incr, max) as being a better metric to prevent excessive localized tissue heating instead of localized peak SAR. However, we note that the exposure time should also be considered in future guidelines. Hence, we advise defining limits on T(incr, max) for specified durations of exposure.

AI evidence extraction

Main findings

Using finite-difference time-domain modeling of six children and two adults exposed to orthogonal plane-wave configurations at ICNIRP reference levels, the authors report that considering uncertainties in model parameters, worst-case scenarios could yield a localized peak temperature increase up to 1 °C. The paper argues that T(incr, max) may be a better metric than localized peak SAR for preventing excessive localized tissue heating and suggests exposure duration should be incorporated into future limits.

Outcomes measured

• Localized peak temperature increase (T(incr, max))
• Whole-body temperature increase (T(body, incr))
• Specific absorption rate metrics (SAR(wb), SAR(10g))
• Uncertainty/sensitivity of modeled temperature increase at ICNIRP reference levels

Limitations

• Theoretical/computational assessment (finite-difference time-domain modeling), not direct measurements in humans
• Results depend on model parameters and uncertainty assumptions (sensitivity study/Monte Carlo noted, but specific parameter ranges not provided in abstract)
• Exposure scenario limited to orthogonal plane-wave configurations

Suggested hubs

• who-icnirp (0.95)
  Study explicitly evaluates exposures at ICNIRP reference levels and discusses guideline metrics/limits.

{
    "study_type": "engineering",
    "exposure": {
        "band": null,
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "30 min (ICNIRP whole-body temperature increase criterion referenced); exposure time discussed as relevant"
    },
    "population": "Six children and two adults (computational models)",
    "sample_size": 8,
    "outcomes": [
        "Localized peak temperature increase (T(incr, max))",
        "Whole-body temperature increase (T(body, incr))",
        "Specific absorption rate metrics (SAR(wb), SAR(10g))",
        "Uncertainty/sensitivity of modeled temperature increase at ICNIRP reference levels"
    ],
    "main_findings": "Using finite-difference time-domain modeling of six children and two adults exposed to orthogonal plane-wave configurations at ICNIRP reference levels, the authors report that considering uncertainties in model parameters, worst-case scenarios could yield a localized peak temperature increase up to 1 °C. The paper argues that T(incr, max) may be a better metric than localized peak SAR for preventing excessive localized tissue heating and suggests exposure duration should be incorporated into future limits.",
    "effect_direction": "mixed",
    "limitations": [
        "Theoretical/computational assessment (finite-difference time-domain modeling), not direct measurements in humans",
        "Results depend on model parameters and uncertainty assumptions (sensitivity study/Monte Carlo noted, but specific parameter ranges not provided in abstract)",
        "Exposure scenario limited to orthogonal plane-wave configurations"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "ICNIRP reference levels",
        "electromagnetic fields",
        "children",
        "adults",
        "finite-difference time-domain (FDTD)",
        "specific absorption rate",
        "SAR(wb)",
        "SAR(10g)",
        "localized tissue heating",
        "peak temperature increase",
        "Monte Carlo analysis",
        "sensitivity analysis"
    ],
    "suggested_hubs": [
        {
            "slug": "who-icnirp",
            "weight": 0.9499999999999999555910790149937383830547332763671875,
            "reason": "Study explicitly evaluates exposures at ICNIRP reference levels and discusses guideline metrics/limits."
        }
    ]
}

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