Extremely Low Frequency Electromagnetic Exposure Assessment in Schools: A Statistical Analysis of Urban and Semi-Urban Areas

Radiation protection dosimetry · 2021 · No effect · Insufficient evidence

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No effectInsufficient evidencePaper 1157

Study snapshot

PublicationRadiation protection dosimetry · 2021

Study typeexposure_assessment

Reported directionNo effect

Evidence ratingInsufficient

Abstract

Extremely Low Frequency Electromagnetic Exposure Assessment in Schools: A Statistical Analysis of Urban and Semi-Urban Areas Y Kiouvrekis, A Alexias, V Softa, M Alkhorayef, A Sulieman, C Tyrakis, C Kappas. Extremely Low Frequency Electromagnetic Exposure Assessment in Schools: A Statistical Analysis of Urban and Semi-Urban Areas. Radiat Prot Dosimetry. 2021 May 28; doi: 10.1093/rpd/ncab076. Abstract The aim of this research paper is to estimate the mean value of extremely low frequency (ELF) exposure in schools in Greece. Detailed ELF measurements were conducted and analyzed by the Weighted Peak Method (WPM), which estimates the overall contribution of electromagnetic waves from 1 Hz to 400 kHz, including their phases. A sample of 243 schools was sampled to calculate. The mean value of ELF magnetic fields (MFs) measured in these two groups comprising 243 schools was the principal focus of interest. ELF MF measurements taken in schools situated both far from and near ELF sources had mean and maximum values well below the current International Commission on Non-Ionizing Radiation Protection (ICNIRP) standard. The mean value of ELF MFs from all sources within the sampled schools in Greece was 0.21 μΤ. A statistically significant difference between the mean MFs measured in the two groups of schools was found, but the MFs in both groups were much lower than the ICNIRP standard. pubmed.ncbi.nlm.nih.gov Excerpts The median value of the MFs measured in the ELF range was 0.174 μΤ, which is 0.174% of the 2010 ICNRP standard (100 μΤ). In Figure 1, we present a typical example, and Table 1 shows the relative contribution of the harmonics.... Mean value is 0.23 μΤ for urban areas and 0.14 μΤ for semi-urban areas with s.d. of 0.23 and 0.13, respectively; the median is 0.18 for the urban area category and 0.11 for the semi-urban category, while the 25 and 75% percentiles are 0.12 μΤ and 0.25 μΤ for urban areas and 0.04 μΤ and 0.18 μΤ for the semi-urban areas, respectively (Figure 4). Similarly, concerning the WPM variable, the mean value is 1.33% for urban areas and 1.20% for semi-urban areas with s.d. of 0.18 and 0.13%, respectively; the median is 1.30% for the urban area category and 1.19% for the semi-urban category, while the 25 and 75% percentiles are 1.25 and 1.36% for urban areas and 1.10 and 1.26% for semi-urban areas, respectively (Figure 4). Conclusions ELF measurements (Max Peak, WPM) in schools situated both far from and near ELF sources allow for a comprehensive assessment of exposure in schools. Furthermore, statistical analysis shows that, on one hand, there is a statistically significant difference between schools in areas described as urban and semi-urban. Despite the fact that there is a statistically significant difference between the levels of MFs measured in schools two separate areas, it is negligible with regard to the current standard by virtue of it being a difference by several orders of magnitude. What is noteworthy is that the WPM values (6–500 Hz range) of the urban and semi-urban schools were found to be approximately an order of magnitude higher than that recorded in WPM frequency range (1 Hz–400 kHz). This is because in semi-urban and urban areas, the mode frequency is 50 Hz due to the power grid. While in terms of the MAX PEAK value, it also makes sense to be different and there is a statistically significant difference, as we are referring to an instantaneous value of each measurement point, which may have been affected but without affecting the final value of the point.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeexposure_assessment

Effect directionno_effect

PopulationSchools in Greece (urban and semi-urban areas)

Sample size243

ExposureELF

Evidence strengthInsufficientConfidence: 78% · Peer reviewed: yes

Main findings

Detailed ELF measurements in 243 schools in Greece (1 Hz–400 kHz, analyzed with the Weighted Peak Method) found mean and maximum ELF magnetic field values well below the ICNIRP 2010 standard (100 µT). The overall mean ELF magnetic field across sampled schools was 0.21 µT (median 0.174 µT). A statistically significant difference in mean magnetic fields between urban and semi-urban schools was reported (urban mean 0.23 µT vs semi-urban mean 0.14 µT), but both were much lower than the ICNIRP standard.

Outcomes measured

ELF magnetic field levels (mean/median/max)
Weighted Peak Method (WPM) exposure metric
Comparison to ICNIRP 2010 reference level (100 µT)
Urban vs semi-urban differences
Near vs far from ELF sources differences

View raw extracted JSON

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "ELF",
    "source": "schools (near vs far from ELF sources; power grid implied)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Schools in Greece (urban and semi-urban areas)",
  "sample_size": 243,
  "outcomes": [
    "ELF magnetic field levels (mean/median/max)",
    "Weighted Peak Method (WPM) exposure metric",
    "Comparison to ICNIRP 2010 reference level (100 µT)",
    "Urban vs semi-urban differences",
    "Near vs far from ELF sources differences"
  ],
  "main_findings": "Detailed ELF measurements in 243 schools in Greece (1 Hz–400 kHz, analyzed with the Weighted Peak Method) found mean and maximum ELF magnetic field values well below the ICNIRP 2010 standard (100 µT). The overall mean ELF magnetic field across sampled schools was 0.21 µT (median 0.174 µT). A statistically significant difference in mean magnetic fields between urban and semi-urban schools was reported (urban mean 0.23 µT vs semi-urban mean 0.14 µT), but both were much lower than the ICNIRP standard.",
  "effect_direction": "no_effect",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF",
    "magnetic fields",
    "schools",
    "Greece",
    "exposure assessment",
    "Weighted Peak Method",
    "WPM",
    "urban",
    "semi-urban",
    "ICNIRP"
  ],
  "suggested_hubs": [
    {
      "slug": "school-wi-fi",
      "weight": 0.22,
      "reason": "Setting is schools, but exposure assessed is ELF magnetic fields rather than Wi‑Fi/RF."
    },
    {
      "slug": "who-icnirp",
      "weight": 0.7,
      "reason": "Findings are explicitly compared against the ICNIRP 2010 standard/reference level."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1093/rpd/ncab076
PubMed: 34047347

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