SAR and temperature elevation in human head due to overexposure to mobile phone radiation with different usage patterns

2019 · Mixed · Low evidence

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MixedLow evidencePaper 1920

Study snapshot

Publicationmanual · 2019

Study typeengineering

Reported directionMixed

Evidence ratingLow

Abstract

SAR and temperature elevation in human head due to overexposure to mobile phone radiation with different usage patterns Bhargava D, Leeprechanon N, Rattanadecho P, Wessapan T. Specific absorption rate and temperature elevation in the human head due to overexposure to mobile phone radiation with different usage patterns. International Journal of Heat and Mass Transfer. 130:1178-1188. March, 2019. doi.org Highlights • The distribution parameters in tissues are significantly influenced by the considered cases. • The temperature increase in the head tissues are lower to cause any thermal damage. • The resultant SAR values in head models for some cases exceed the ICNIRP 2 W/kg exposure limit. Abstract Accidental overexposure to non-standard mobile phone radiation can occur in many situations. The overpower limit of mobile phone radiation interacts with the human body which could result in an adverse effect on human health. It is envisaged that the severity of the physiological effect can take place with small temperature increase in the delicate organs or tissues such as eyes, brain, skin, etc. However, the resulting thermo- physiological response of the body tissues to overpower limit of mobile phone radiation is still not well implemented. The aim of this study is to analyze the effect of overexposure of mobile phone radiation on the specific absorption rate (SAR) and temperature increase in three-dimensional heterogeneous human head models. The study focuses attention on the differences in the electromagnetic (EM) absorption characteristics with higher power level among different usage pattern. The effect of three different usage patterns - voice calling, video calling, and texting- on SAR and temperature distributions in different types of head tissues is systematically investigated. This paper also investigates the effects of different user ages, radiated powers, and gap distances between mobile phone and human heads, on SAR and temperature distributions. Results obtained from this analysis considering the safety guidelines show a high impact of mobile phone radiation in the voice calling position. Hence, comparisons of the absorption of mobile phone radiation are calculated between an adult and a 7-year-old child head model, for the voice calling position at different gap distances. In addition, the results indicate that child head always has a higher absorption rate of mobile phone radiation than the adult head. The rate of absorption in tissue increases as the distance between mobile phone and head decreases and the radiated power increases, depending on their dielectric and thermal properties. The obtained results can be helpful in determining exposure limits for the power output of the mobile phone, and the distance a user should maintain from the mobile phone in thermo-physiological aspects. Conclusion The paper investigates the increase in SAR and temperature in anatomical human head models of child and adult in overexposure situations. The comparison of the three different mobile phone usage patterns is studied when the head models are exposed to mobile phone radiation at 900 MHz frequency and 5 W radiating power. The study also includes a comparison of the distribution parameters in child and adult heads, effect of different gap distances and radiated powers. The results show that among all the cases, the SAR and temperature increase are found to be highest in the voice calling case for 0.5 cm gap distance and 5 W radiated power. Also, it is evident from the results that the SAR and temperature increase in the tissues do not directly correspond to each other but are related to the physical parameters of biological tissues such as thermal conductivity, dielectric properties, blood perfusion rate, etc. This shows the importance of performing transient thermal analysis along with the dosimetry analysis to clearly understand the interaction between mobile phone radiation and human tissues. Comparing to the ICNIRP exposure limit, the resulting SAR values in skin layer, in voice and video calling cases, are found to exceed the exposure limit. But, comparing the temperature increase in the brain, it does not approach the possible physiological damage. This study shows the concern regarding the non-standard mobile phone devices which may be harmful to human health from excessive radiation power. Moreover, the obtained results from the study also show that the children are more exposed and have a greater possibility of a serious adverse effect than the adult when exposed to mobile phone radiation. phadungsak.me.engr.tu.ac.th 01%20%20inter%20J%20heat&mass%20transfer.pdf

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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 directionmixed

PopulationThree-dimensional heterogeneous human head models (adult and 7-year-old child)

Sample sizeNot supplied

ExposureRF · 900 MHz

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Modeling of overexposure scenarios (e.g., 5 W radiating power at 900 MHz) found the highest SAR and temperature increases in the voice-calling position, especially at small phone–head gap distances (e.g., 0.5 cm). The child head model showed higher absorption (SAR) than the adult head model across conditions. For some cases (voice and video calling), SAR in the skin layer exceeded the ICNIRP 2 W/kg limit, while the temperature increase in the brain was reported as not approaching possible physiological damage.

Outcomes measured

Specific absorption rate (SAR) distribution in head tissues
Temperature increase/elevation in head tissues
Comparison to ICNIRP 2 W/kg SAR exposure limit

Limitations

Computational/modeling study in anatomical head models; no direct human health outcomes measured
Exposure described as non-standard/overexposure (e.g., 5 W) which may not represent typical consumer phone use
Sample size and model validation details not provided in the abstract

View raw extracted JSON

{
  "study_type": "engineering",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 900,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Three-dimensional heterogeneous human head models (adult and 7-year-old child)",
  "sample_size": null,
  "outcomes": [
    "Specific absorption rate (SAR) distribution in head tissues",
    "Temperature increase/elevation in head tissues",
    "Comparison to ICNIRP 2 W/kg SAR exposure limit"
  ],
  "main_findings": "Modeling of overexposure scenarios (e.g., 5 W radiating power at 900 MHz) found the highest SAR and temperature increases in the voice-calling position, especially at small phone–head gap distances (e.g., 0.5 cm). The child head model showed higher absorption (SAR) than the adult head model across conditions. For some cases (voice and video calling), SAR in the skin layer exceeded the ICNIRP 2 W/kg limit, while the temperature increase in the brain was reported as not approaching possible physiological damage.",
  "effect_direction": "mixed",
  "limitations": [
    "Computational/modeling study in anatomical head models; no direct human health outcomes measured",
    "Exposure described as non-standard/overexposure (e.g., 5 W) which may not represent typical consumer phone use",
    "Sample size and model validation details not provided in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "mobile phone radiation",
    "overexposure",
    "900 MHz",
    "5 W",
    "specific absorption rate",
    "SAR",
    "temperature elevation",
    "human head model",
    "child vs adult",
    "usage patterns",
    "voice calling",
    "video calling",
    "texting",
    "gap distance",
    "ICNIRP 2 W/kg"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.72,
      "reason": "Explicit comparison to ICNIRP 2 W/kg SAR exposure limit."
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}

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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: 10.1016/j.ijheatmasstransfer.2018.11.031
PubMed: Not supplied

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