SAR Estimations in a Classroom with Wireless Computers

Authors: Soares NE, Bulla G, Fernández-Rodríguez CE, de Salles AAA

Year: 2025

Category: Electromagnetic Safety, Bioelectromagnetics

Journal: J. Microw. Optoelectron. Electromagn. Appl.

DOI: 10.1590/2179-10742025v24i3288526

URL: https://www.scielo.br/j/jmoea/a/hS9VJvKddrTsTtyqLrVdNZx/?lang=en#

Abstract

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.
SAR wireless laptops classroom exposure EMF children health risk mitigation
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