Extremely low frequency magnetic fields (ELF-MF) in Switzerland: From exposure monitoring to daily

Abstract

Extremely low frequency magnetic fields (ELF-MF) in Switzerland: From exposure monitoring to daily exposure scenarios Loizeau N, Haas D, Zahner M, Stephan C, Schindler J, Gugler M, Fröhlich J, Ziegler T, Röösli M. Extremely low frequency magnetic fields (ELF-MF) in Switzerland: From exposure monitoring to daily exposure scenarios. Environment International. 2024. doi: 10.1016/j.envint.2024.109181. Abstract Exposure to extremely low frequency magnetic fields (ELF-MF) is ubiquitous in our daily environment. This study aims to provide a comprehensive overview of the ambient ELF-MF exposure in Switzerland and presents a novel environmental exposure matrix for exposure assessment and risk communication. Magnetic flux density levels (μT) were measured using a portable exposimeter carried in a backpack for the main ELF sources: railway power (16.7 Hz), domestic power (50 Hz), and tram ripple current (300 Hz). We collected ELF-MF levels between 2022 and 2024 in various environments representative of the Swiss population: 300 outdoor areas (e.g. city centres, residential areas), 245 public spaces (e.g. train stations, schools), 348 transport journeys (e.g. train, cars), and in 59 homes (e.g. bedrooms, living rooms). Over all environments, the highest ELF-MF exposure levels were measured in train stations (median: 0.48 μT), trains (median: 0.40 μT), and in living rooms near (<200 m) highest voltage lines of 220 kV and 380 kV (median: 0.37 μT). ELF-MF median levels measured two years apart showed high Pearson correlation coefficients in the same 150 outdoor areas (r = 0.88) and 86 public spaces (r = 0.87), without any significant changes. All measurements are well below the Swiss ambient regulatory limit based on the ICNIRP 1998 guidelines (median: 0.2 %). Finally, we derived an environmental exposure matrix and modelled 27 daily time-weighted average ELF-MF exposure scenarios by combining typical time spent at home, work and transport environments. People who do not live near highest voltage lines or work in highly exposed environments are typically exposed to less than 0.3 μT on average, while those who do are likely to exceed this level. This novel environmental exposure matrix is a useful tool for public communication and agent-based exposure modelling for future epidemiological research. Open access paper: sciencedirect.com

AI evidence extraction

Main findings

Portable exposimeter measurements (2022–2024) found the highest median ELF-MF levels in train stations (0.48 μT), trains (0.40 μT), and living rooms near (<200 m) 220/380 kV lines (0.37 μT). Repeated measurements two years apart in the same locations showed high correlations (outdoor areas r=0.88; public spaces r=0.87) with no significant changes. All measurements were reported as well below the Swiss ambient regulatory limit (median 0.2% of the limit), and modelled daily time-weighted average scenarios suggested typical exposures <0.3 μT unless living near highest voltage lines or working in highly exposed environments.

Outcomes measured

• Magnetic flux density (μT) levels across environments
• Temporal stability of ELF-MF levels (Pearson correlation over two years)
• Comparison to Swiss ambient regulatory limit (ICNIRP 1998-based)
• Modelled daily time-weighted average exposure scenarios

Suggested hubs

• who-icnirp (0.6)
  Mentions Swiss ambient regulatory limit based on ICNIRP 1998 guidelines.
• occupational-exposure (0.35)
  Daily exposure scenarios include work in highly exposed environments (no specific occupation detailed).

{
    "study_type": "exposure_assessment",
    "exposure": {
        "band": "ELF",
        "source": "environmental (railway power, domestic power, tram ripple current; proximity to high-voltage lines)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "Measurements collected between 2022 and 2024; daily time-weighted average scenarios modelled"
    },
    "population": "Environments representative of the Swiss population (outdoor areas, public spaces, transport journeys, homes)",
    "sample_size": 952,
    "outcomes": [
        "Magnetic flux density (μT) levels across environments",
        "Temporal stability of ELF-MF levels (Pearson correlation over two years)",
        "Comparison to Swiss ambient regulatory limit (ICNIRP 1998-based)",
        "Modelled daily time-weighted average exposure scenarios"
    ],
    "main_findings": "Portable exposimeter measurements (2022–2024) found the highest median ELF-MF levels in train stations (0.48 μT), trains (0.40 μT), and living rooms near (<200 m) 220/380 kV lines (0.37 μT). Repeated measurements two years apart in the same locations showed high correlations (outdoor areas r=0.88; public spaces r=0.87) with no significant changes. All measurements were reported as well below the Swiss ambient regulatory limit (median 0.2% of the limit), and modelled daily time-weighted average scenarios suggested typical exposures <0.3 μT unless living near highest voltage lines or working in highly exposed environments.",
    "effect_direction": "unclear",
    "limitations": [],
    "evidence_strength": "insufficient",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "unknown",
    "keywords": [
        "extremely low frequency",
        "ELF-MF",
        "magnetic fields",
        "exposure monitoring",
        "portable exposimeter",
        "Switzerland",
        "railway power",
        "domestic power",
        "tram ripple current",
        "high-voltage lines",
        "exposure matrix",
        "time-weighted average",
        "ICNIRP 1998",
        "regulatory limit"
    ],
    "suggested_hubs": [
        {
            "slug": "who-icnirp",
            "weight": 0.59999999999999997779553950749686919152736663818359375,
            "reason": "Mentions Swiss ambient regulatory limit based on ICNIRP 1998 guidelines."
        },
        {
            "slug": "occupational-exposure",
            "weight": 0.34999999999999997779553950749686919152736663818359375,
            "reason": "Daily exposure scenarios include work in highly exposed environments (no specific occupation detailed)."
        }
    ]
}

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