Assessment of Radiofrequency Exposure in the Vicinity of School Environments in Crete Island, South Greece

2022 · Unclear · Moderate evidence

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UnclearModerate evidencePaper 775

Study snapshot

Publicationmanual · 2022

Study typeexposure_assessment

Reported directionUnclear

Evidence ratingModerate

Abstract

Assessment of Radiofrequency Exposure in the Vicinity of School Environments in Crete Island, South Greece Theodore N. Kapetanakis, Melina P. Ioannidou, Anargyros T. Baklezos, Christos D. Nikolopoulos, Eleftheria S. Sergaki, Antonios J. Konstantaras, Ioannis O. Vardiambasis. 2022. Assessment of Radiofrequency Exposure in the Vicinity of School Environments in Crete Island, South Greece. Applied Sciences 12(9):4701. doi: org/10.3390/app12094701 Abstract This study aimed to estimate the radiofrequency exposure levels in the vicinity of nursery and primary schools at the northwest part of Crete island in Greece. Moreover, the compliance with the exposure limits, according to Greek legislation, was investigated. A total of 396 in situ frequency-selective and broadband measurements were conducted around 69 schools, classified in urban and suburban environments, in the range of 27–3000 MHz (subdivided in seven frequency bands). The measured value of the electric field strength (V/m) was recorded and, subsequently, the exposure ratio was calculated. Statistical analysis was performed in order to analyze and evaluate the data. In addition, a worst-case scenario was examined by considering the highest measured exposure level around each school. The statistical tests indicated that the mean and median values of the exposure ratio, even in the worst-case scenario, were found well below 1 for all frequency bands. The calculated distributions of the electric field measurements demonstrated that almost 90% of the latter were below 1 V/m, with the majority of values lying in the range of 0.5–1 V/m. The main contributors to the total exposure were the mobile communication frequencies and broadcasting, while the exposure was greater in urban than in suburban environments. Conclusions In conclusion, our results indicate that, in the vast majority of cases, we observed compliance with the Greek established reference levels for RF exposure. The median values of the exposure ratio were found less than 0.035 in all cases examined, whereas the maximum values of the exposure ratio lay below 0.28 except for a very few cases, where the maximum value of the E-field strength exceeded the reference level. Most recordings of the electric field strength (i.e., 90%) were found lower than 1 V/m, while the majority of the total exposure ratio values (i.e., almost 94%) were below 0.2. The median values of the E-field strength were found to be statistically significantly different in urban and suburban environments, except for the 27–879 MHz band where broadcast applications dominate. Readings were slightly higher in urban areas than in the suburbs and the latter exhibited a narrower interquartile range than the former due to their more uniform construction. We also found that mobile communication frequencies and broadcast were the sources that contributed most to the total exposure. Our future plans include EMF measurements not only around but also inside schools and classrooms, in the frequency range of 27 MHz–6 GHz, especially with the prospect of the rapidly upcoming 5G mobile services everywhere. A comparison of the electric field strength at the same measurement locations, before and after the advent of 5G, will be interesting and revealing. Open access paper: mdpi.com

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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 typeexposure_assessment

Effect directionunclear

PopulationNot supplied

Sample size396

ExposureRF

Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

Across 396 in situ frequency-selective and broadband measurements around 69 nursery and primary schools (27–3000 MHz), mean and median exposure ratios were well below 1 for all frequency bands, including a worst-case scenario using the highest measured level per school. About 90% of electric field measurements were below 1 V/m, and most exposure ratio values (~94%) were below 0.2; maximum exposure ratios were below 0.28 except for a very few cases where maximum E-field exceeded the reference level. Mobile communication frequencies and broadcasting were the main contributors, and exposure was higher in urban than suburban environments.

Outcomes measured

Electric field strength (V/m)
Exposure ratio vs Greek reference levels/limits
Compliance with Greek RF exposure limits
Urban vs suburban differences
Frequency-band contributors to total exposure

Limitations

Measurements were conducted around schools (vicinity) rather than inside schools/classrooms (authors note future plans to measure indoors).
Geographic scope limited to the northwest part of Crete island, Greece.
Frequency range limited to 27–3000 MHz (authors mention future plans up to 6 GHz).
Compliance assessed against Greek legislation/reference levels; results may not generalize to other standards.

View raw extracted JSON

{
  "study_type": "exposure_assessment",
  "exposure": {
    "band": "RF",
    "source": "school environment vicinity (ambient sources incl. mobile communications and broadcasting)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": 396,
  "outcomes": [
    "Electric field strength (V/m)",
    "Exposure ratio vs Greek reference levels/limits",
    "Compliance with Greek RF exposure limits",
    "Urban vs suburban differences",
    "Frequency-band contributors to total exposure"
  ],
  "main_findings": "Across 396 in situ frequency-selective and broadband measurements around 69 nursery and primary schools (27–3000 MHz), mean and median exposure ratios were well below 1 for all frequency bands, including a worst-case scenario using the highest measured level per school. About 90% of electric field measurements were below 1 V/m, and most exposure ratio values (~94%) were below 0.2; maximum exposure ratios were below 0.28 except for a very few cases where maximum E-field exceeded the reference level. Mobile communication frequencies and broadcasting were the main contributors, and exposure was higher in urban than suburban environments.",
  "effect_direction": "unclear",
  "limitations": [
    "Measurements were conducted around schools (vicinity) rather than inside schools/classrooms (authors note future plans to measure indoors).",
    "Geographic scope limited to the northwest part of Crete island, Greece.",
    "Frequency range limited to 27–3000 MHz (authors mention future plans up to 6 GHz).",
    "Compliance assessed against Greek legislation/reference levels; results may not generalize to other standards."
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency exposure",
    "school environments",
    "electric field strength",
    "exposure ratio",
    "compliance",
    "frequency-selective measurements",
    "broadband measurements",
    "urban",
    "suburban",
    "mobile communications",
    "broadcasting",
    "Greece",
    "Crete",
    "27–3000 MHz"
  ],
  "suggested_hubs": [
    {
      "slug": "school-wi-fi",
      "weight": 0.62,
      "reason": "RF exposure assessment conducted in the vicinity of nursery and primary schools; school environment is central (though sources include mobile/broadcast rather than explicitly Wi‑Fi)."
    }
  ]
}

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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: 10.3390/app12094701
PubMed: Not supplied

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