The human skin as a sub-THz receiver - Does 5G pose a danger to it or not?

Abstract

The human skin as a sub-THz receiver - Does 5G pose a danger to it or not? Betzalel N, Ben Ishai P, Feldman Y. The human skin as a sub-THz receiver - Does 5G pose a danger to it or not? Environ Res. 2018 May;163:208-216. doi: 10.1016/j.envres.2018.01.032. Highlights • The sweat duct is regarded as a helical antenna in the sub-THz band, reflectance depends on perspiration. • We outline the background for non-thermal effects based on the structure of sweat ducts. • We have introduced a realistic skin EM model and found the expected SAR for the 5G standard. Abstract In the interaction of microwave radiation and human beings, the skin is traditionally considered as just an absorbing sponge stratum filled with water. In previous works, we showed that this view is flawed when we demonstrated that the coiled portion of the sweat duct in upper skin layer is regarded as a helical antenna in the sub-THz band. Experimentally we showed that the reflectance of the human skin in the sub-THz region depends on the intensity of perspiration, i.e. sweat duct's conductivity, and correlates with levels of human stress (physical, mental and emotional). Later on, we detected circular dichroism in the reflectance from the skin, a signature of the axial mode of a helical antenna. The full ramifications of what these findings represent in the human condition are still unclear. We also revealed correlation of electrocardiography (ECG) parameters to the sub-THz reflection coefficient of human skin. In a recent work, we developed a unique simulation tool of human skin, taking into account the skin multi-layer structure together with the helical segment of the sweat duct embedded in it. The presence of the sweat duct led to a high specific absorption rate (SAR) of the skin in extremely high frequency band. In this paper, we summarize the physical evidence for this phenomenon and consider its implication for the future exploitation of the electromagnetic spectrum by wireless communication. Starting from July 2016 the US Federal Communications Commission (FCC) has adopted new rules for wireless broadband operations above 24 GHz (5 G). This trend of exploitation is predicted to expand to higher frequencies in the sub-THz region. One must consider the implications of human immersion in the electromagnetic noise, caused by devices working at the very same frequencies as those, to which the sweat duct (as a helical antenna) is most attuned. We are raising a warning flag against the unrestricted use of sub-THz technologies for communication, before the possible consequences for public health are explored. ncbi.nlm.nih.gov Excerpt The need for high data transmission rates, coupled with advances in semiconductor technology, is pushing the communications industry towards the sub-THz frequency spectrum. While the promises of a glorious future, resplendent with semi-infinite data streaming, may be attractive, there is a price to pay for such luxury. We shall find our cities, workspace and homes awash with 5 G base stations and we shall live though an unprecedented EM smog. The benefits to our society of becoming so wired cannot ignore possible health concerns, as yet unexplored. There is enough evidence to suggest that the combination of the helical sweat duct and wavelengths approaching the dimensions of skin layers could lead to non-thermal biological effects. Such fears should be investigated and these concerns should also effect the definition of standards for the application of 5G communications. Prior study: Betzalel N, Feldman Y, Ishai PB. The Modeling of the Absorbance of Sub-THz Radiation by Human Skin. IEEE Transactions on Terahertz Science and Technology 7(5):521-528. Sep 2017. Abstract In the near future, applications will come online that require data transmission in ultrahigh rates of 100 Gbit per second and beyond. In fact, the planning for new industry regulations for the exploitation of the sub-THz band are well advanced under the auspices of IEEE 802.15 Terahertz Interest Group. One aspect of this endeavor is to gauge the possible impact on human health by the expected explosion in commercial use of this band. It is, therefore, imperative to estimate the respective specific absorption rates of human tissues. In the interaction of microwave radiation and human beings, the skin is traditionally considered as just an absorbing sponge stratum filled with water. This approach is justified when the impinging wavelength is greater than the dimensions of the skin layer. However, in the sub-THz band this condition is violated. In 2008, we demonstrated that the coiled portion of the sweat duct in upper skin layer could be regarded as a helical antenna in the sub-THz band. The full ramifications of what these findings represent in the human condition are still very unclear, but it is obvious that the absorption of electromagnetic energy is governed by the topology for the skin and its organelles, especially the sweat duct. Conclusion The need for high data transmission rates, coupled with advances in semiconductor technology, is pushing the communications industry toward the sub-THz frequency spectrum. While this is a relatively underutilized area of the EM spectrum, it does come with a price. The affinity of atmospheric absorption in this band means that many small short range and relatively powerful transmitters will be required for decent coverage. The results of our study emphasize that rather than gallop toward these solutions with abandon, the human health implications must be considered first, as wavelengths approach the dimensions of skin-based features. The results point to the dominant role of the sweat duct in EM skin absorbance. We can conclude and say that if the new regime of WLAN communication, the 5G standard, will happen in the next years, the concern regarding biological influence on the human body should be considered. ieeexplore.ieee.org

AI evidence extraction

Main findings

The paper summarizes prior physical/experimental observations and introduces/uses a multi-layer skin electromagnetic model including a helical sweat duct segment; the presence of the sweat duct is reported to lead to high SAR in the skin in the extremely high frequency band. The authors state that implications for public health are unclear and raise a warning flag regarding unrestricted use of sub-THz/5G technologies before possible consequences are explored.

Outcomes measured

• Skin reflectance in sub-THz region (dependence on perspiration/sweat duct conductivity)
• Circular dichroism in skin reflectance (interpreted as axial mode of helical antenna)
• Correlation of ECG parameters with sub-THz skin reflection coefficient
• Specific absorption rate (SAR) in skin in extremely high frequency band (simulation/modeling)
• Potential non-thermal biological effects (discussed as a concern)

Limitations

• Full ramifications of the reported findings for human health are stated to be unclear
• Health consequences are discussed as concerns rather than demonstrated outcomes in this abstract
• Key quantitative exposure parameters (exact frequencies, SAR values) are not provided in the abstract

Suggested hubs

• 5g-policy (0.86)
  Discusses FCC rules above 24 GHz for 5G and raises concerns about unrestricted sub-THz/5G deployment.

{
    "study_type": "review",
    "exposure": {
        "band": "sub-THz / extremely high frequency (mmWave)",
        "source": "5G wireless communications (base stations/devices)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Human skin (modeled; prior experimental reflectance observations referenced)",
    "sample_size": null,
    "outcomes": [
        "Skin reflectance in sub-THz region (dependence on perspiration/sweat duct conductivity)",
        "Circular dichroism in skin reflectance (interpreted as axial mode of helical antenna)",
        "Correlation of ECG parameters with sub-THz skin reflection coefficient",
        "Specific absorption rate (SAR) in skin in extremely high frequency band (simulation/modeling)",
        "Potential non-thermal biological effects (discussed as a concern)"
    ],
    "main_findings": "The paper summarizes prior physical/experimental observations and introduces/uses a multi-layer skin electromagnetic model including a helical sweat duct segment; the presence of the sweat duct is reported to lead to high SAR in the skin in the extremely high frequency band. The authors state that implications for public health are unclear and raise a warning flag regarding unrestricted use of sub-THz/5G technologies before possible consequences are explored.",
    "effect_direction": "unclear",
    "limitations": [
        "Full ramifications of the reported findings for human health are stated to be unclear",
        "Health consequences are discussed as concerns rather than demonstrated outcomes in this abstract",
        "Key quantitative exposure parameters (exact frequencies, SAR values) are not provided in the abstract"
    ],
    "evidence_strength": "very_low",
    "confidence": 0.66000000000000003108624468950438313186168670654296875,
    "peer_reviewed_likely": "yes",
    "keywords": [
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        "sub-THz",
        "mmWave",
        "extremely high frequency",
        "human skin",
        "sweat duct",
        "helical antenna",
        "reflectance",
        "circular dichroism",
        "SAR",
        "non-thermal effects",
        "FCC 24 GHz"
    ],
    "suggested_hubs": [
        {
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