Influence of Materials, Windows &Shielding Layers on Low-Frequency Electromagnetic Environment of Subway Vehicle & Human Exposure Research

2021 · No effect · Low evidence

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No effectLow evidencePaper 994

Study snapshot

Publicationmanual · 2021

Study typeengineering

Reported directionNo effect

Evidence ratingLow

Abstract

Influence of Materials, Windows &Shielding Layers on Low-Frequency Electromagnetic Environment of Subway Vehicle & Human Exposure Research Zhiyuan Wang, Weinan Liu. Influence of Materials, Windows and Shielding Layers on Low-Frequency Electromagnetic Environment of Subway Vehicle and Human Exposure Research. Progress In Electromagnetics Research M, 105:151-160, 2021. doi:10.2528/PIERM21080403. Abstract The numerous high-power devices and cables gathered around the subway vehicle will aggravate the deterioration of the electromagnetic environment, which may cause the train to fail to operate normally or threaten the health of passengers with a pacemaker or defibrillator. In order to study the distribution characteristics of low-frequency magnetic field of the subway in complex electromagnetic environment and the influence of various factors on human electromagnetic exposure, the magnetic flux density nephograms of the subway train with different vehicle body materials, with or without windows and with the shielding layer are calculated and analyzed. Specific energy absorption rate (SAR) values have been calculated in a standing voxel model from exposure to electromagnetic fields at 2.4 GHz, frequencies commonly used by Wi-Fi devices. The numerical results show that the average value of magnetic flux density in the stainless-steel carriage is less than that in the aluminum alloy carriage and the carbon fiber reinforce plastic (CFRP) carriage. Compared with the vehicle with windows, the average value of magnetic flux density in the vehicle without windows is less. The added shielding layer decreases the average value of magnetic flux density from 10.5 uT to 3 uT. The maximum value of magnetic flux density in the carriage under different factors is about 10 uT, which is far less than the magnetic flux density reference limit of 0.1 mT of the International Commission of Non-Ionizing Radiation Protection (ICNIRP) standard. When the Wi-Fi device is closest to the human body, the highest Specific Absorption Ratio (SAR) value of human tissue is 0.00749 W/kg, which is far less than the electromagnetic exposure limit of 1.6 W/kg of IEEE standard. jpier.org

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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 typeengineering

Effect directionno_effect

PopulationNot supplied

Sample sizeNot supplied

Exposuremixed · 2400 MHz · 0.00749 W/kg

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Numerical calculations indicated lower average magnetic flux density in a stainless-steel carriage compared with aluminum alloy and CFRP, lower average magnetic flux density without windows than with windows, and a reduction in average magnetic flux density from 10.5 µT to 3 µT with an added shielding layer. The maximum magnetic flux density under different factors was about 10 µT, reported as far below the ICNIRP reference limit of 0.1 mT. For 2.4 GHz exposure with a Wi-Fi device closest to the body, the highest reported SAR in human tissue was 0.00749 W/kg, reported as far below the IEEE limit of 1.6 W/kg.

Outcomes measured

Magnetic flux density (µT) distribution in subway carriage under different materials/windows/shielding
Specific absorption rate (SAR) in a standing voxel model at 2.4 GHz
Comparison to ICNIRP magnetic flux density reference limit (0.1 mT)
Comparison to IEEE SAR exposure limit (1.6 W/kg)

View raw extracted JSON

{
  "study_type": "engineering",
  "exposure": {
    "band": "mixed",
    "source": "subway vehicle environment; wi-fi device",
    "frequency_mhz": 2400,
    "sar_wkg": 0.00749,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Magnetic flux density (µT) distribution in subway carriage under different materials/windows/shielding",
    "Specific absorption rate (SAR) in a standing voxel model at 2.4 GHz",
    "Comparison to ICNIRP magnetic flux density reference limit (0.1 mT)",
    "Comparison to IEEE SAR exposure limit (1.6 W/kg)"
  ],
  "main_findings": "Numerical calculations indicated lower average magnetic flux density in a stainless-steel carriage compared with aluminum alloy and CFRP, lower average magnetic flux density without windows than with windows, and a reduction in average magnetic flux density from 10.5 µT to 3 µT with an added shielding layer. The maximum magnetic flux density under different factors was about 10 µT, reported as far below the ICNIRP reference limit of 0.1 mT. For 2.4 GHz exposure with a Wi-Fi device closest to the body, the highest reported SAR in human tissue was 0.00749 W/kg, reported as far below the IEEE limit of 1.6 W/kg.",
  "effect_direction": "no_effect",
  "limitations": [],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "subway vehicle",
    "low-frequency magnetic field",
    "magnetic flux density",
    "shielding layer",
    "windows",
    "materials",
    "stainless steel",
    "aluminum alloy",
    "CFRP",
    "SAR",
    "2.4 GHz",
    "Wi-Fi",
    "ICNIRP",
    "IEEE"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.32,
      "reason": "Study concerns EMF environment and exposure in a subway vehicle setting (transport/operational environment)."
    },
    {
      "slug": "school-wi-fi",
      "weight": 0.12,
      "reason": "Includes SAR calculations at 2.4 GHz from Wi‑Fi devices (general Wi‑Fi exposure context)."
    },
    {
      "slug": "who-icnirp",
      "weight": 0.28,
      "reason": "Explicit comparison to ICNIRP reference limit."
    }
  ]
}

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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: 10.2528/pierm21080403
PubMed: Not supplied

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