SAR Estimations in a Classroom with Wireless Computers

Abstract

Category: Electromagnetic Safety, Bioelectromagnetics Tags: SAR, wireless laptops, classroom exposure, EMF, children, health risk, mitigation DOI: 10.1590/2179-10742025v24i3288526 URL: scielo.br Overview This research provides a detailed examination of peak spatial Specific Absorption Rate (psSAR) among students of different ages in classrooms equipped with wireless computers. Motivated by the increasing use of electronic devices in education, the study aims to assess implications for radio-frequency exposure in these environments. Methods - Simulated two classroom scenarios: one with several 7-year-old children, another with 43-year-old adults, each using a laptop. - Calculated 1 g and 10 g psSAR for the head, back, and hands. - Varied distances between students; results compared to single-student setups. - Utilized the 2.45 GHz Wi-Fi band per IEEE 802.11-2020, with laptops operating at 100 mW power. Findings - A small increase in row spacing (e.g., 10 cm) can reduce classroom psSAR by about 13 dB. - Maximum simulated psSAR values were below recommended ICNIRP and IEEE limits, but classroom arrangements can significantly amplify exposure (e.g., up to 26 dB greater in the back, 4-fold in the hands, 45-fold in the head compared to single-user setups). - psSAR hotspots shift position with changing desk distances due to complex electromagnetic field interactions. Implications & Health Risk - Even when below established safety limits, long-term, low-level EMF exposure remains a concern, especially for children who occupy classrooms for extended periods. The study underscores possible biochemical effects from chronic exposure, which are not captured in simulations but are known health risks linked to EMF. - Simultaneous use of other EMF sources like smartphones may further increase exposure levels and should be included in future assessments. Conclusion & Recommendations - Increasing the distance between student's desks reduces EMF exposure—e.g., a 5 cm increase cuts exposure by about 63%, a 50 cm increase by about 90%. - To reduce EMF health risks, the authors advise avoiding wireless communications in areas of prolonged occupancy (classrooms, libraries, offices, homes) and using wired connections instead (such as ethernet or fiber optic), with added benefits of higher bandwidth and lower energy consumption.

AI evidence extraction

Main findings

Simulations at 2.45 GHz (IEEE 802.11-2020) with laptops at 100 mW found maximum 1 g and 10 g psSAR values below recommended ICNIRP and IEEE limits. Classroom arrangements could substantially increase psSAR versus single-user setups (reported up to 26 dB greater in the back, 4-fold in the hands, and 45-fold in the head), while increasing spacing between rows/desks reduced psSAR (e.g., ~13 dB reduction with 10 cm increase; ~63% reduction with 5 cm increase; ~90% reduction with 50 cm increase).

Outcomes measured

• Peak spatial SAR (psSAR) 1 g
• Peak spatial SAR (psSAR) 10 g
• psSAR in head
• psSAR in back
• psSAR in hands
• Effect of desk/row spacing on psSAR
• Comparison of multi-user classroom vs single-user setup
• Compliance relative to ICNIRP and IEEE limits

Limitations

• Results are based on simulations (not measurements).
• Only Wi‑Fi at 2.45 GHz and laptops at 100 mW are described; other sources (e.g., smartphones) are noted as not included.
• Health effects are discussed as concerns but not directly assessed (no biological/clinical outcomes).

Suggested hubs

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  Simulated RF exposure/SAR in classrooms using Wi‑Fi laptops; mitigation via spacing and wired alternatives.
• who-icnirp (0.6)
  Findings explicitly compared to ICNIRP (and IEEE) exposure limits.

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    "study_type": "exposure_assessment",
    "exposure": {
        "band": "RF",
        "source": "Wi‑Fi (wireless laptops in classroom)",
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Simulated classroom scenarios with 7-year-old children and 43-year-old adults (each using a laptop).",
    "sample_size": null,
    "outcomes": [
        "Peak spatial SAR (psSAR) 1 g",
        "Peak spatial SAR (psSAR) 10 g",
        "psSAR in head",
        "psSAR in back",
        "psSAR in hands",
        "Effect of desk/row spacing on psSAR",
        "Comparison of multi-user classroom vs single-user setup",
        "Compliance relative to ICNIRP and IEEE limits"
    ],
    "main_findings": "Simulations at 2.45 GHz (IEEE 802.11-2020) with laptops at 100 mW found maximum 1 g and 10 g psSAR values below recommended ICNIRP and IEEE limits. Classroom arrangements could substantially increase psSAR versus single-user setups (reported up to 26 dB greater in the back, 4-fold in the hands, and 45-fold in the head), while increasing spacing between rows/desks reduced psSAR (e.g., ~13 dB reduction with 10 cm increase; ~63% reduction with 5 cm increase; ~90% reduction with 50 cm increase).",
    "effect_direction": "mixed",
    "limitations": [
        "Results are based on simulations (not measurements).",
        "Only Wi‑Fi at 2.45 GHz and laptops at 100 mW are described; other sources (e.g., smartphones) are noted as not included.",
        "Health effects are discussed as concerns but not directly assessed (no biological/clinical outcomes)."
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "SAR",
        "psSAR",
        "Wi‑Fi",
        "2.45 GHz",
        "IEEE 802.11-2020",
        "wireless laptops",
        "classroom",
        "children",
        "exposure assessment",
        "ICNIRP",
        "IEEE limits",
        "mitigation",
        "desk spacing"
    ],
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}

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