比吸収率(ひきゅうしゅうりつ、SAR : specific absorption rate)とは、無線周波数(RF)の電磁界(電磁波)に曝露された人体に吸収されるエネルギー量の尺度である。また、超音波などの他の形態のエネルギーについても用いることがある[1]。比吸収率は、組織の単位質量あたりに吸収する仕事率(電力)として定義され、ワット毎キログラム(W/kg)の単位で表される[2][3]。
FCCによるガイド"Specific Absorption Rate (SAR) For Cell Phones: What It Means For You"(携帯電話の比吸収率(SAR):何を意味するのか)には、SAR値の制限を詳しく説明した後で、次のような「要点」の論説が掲載されている。
"ALL cell phones must meet the FCC’s RF exposure standard, which is set at a level well below that at which laboratory testing indicates, and medical and biological experts generally agree, adverse health effects could occur. For users who are concerned with the adequacy of this standard or who otherwise wish to further reduce their exposure, the most effective means to reduce exposure are to hold the cell phone away from the head or body and to use a speakerphone or hands-free accessory. These measures will generally have much more impact on RF energy absorption than the small difference in SAR between individual cell phones, which, in any event, is an unreliable comparison of RF exposure to consumers, given the variables of individual use." [9]
^Sun, J; Hynynen, K (2013-08-12). “Focusing of therapeutic ultrasound through a human skull: a numerical study”. J Acoust Soc Am104 (3 Pt 1): 1705–15. Bibcode: 1998ASAJ..104.1705S. doi:10.1121/1.424383. PMID 9745750.
^Jin, Jianming (1998). Electromagnetic Analysis and Design in Magnetic Resonance Imaging. CRC Press. pp. §5.3.3 pp. 226ff. ISBN 978-0-8493-9693-9
^Kshetrimayum, Rakhesh Singh (March-April 2008). “Mobile Phones: Bad for your Health?”. IEEE Potentials27 (2): 18–20. doi:10.1109/MPOT.2008.919701. http://ieeexplore.ieee.org/document/4475802/?arnumber=4475802.
^“ICNIRP Guidelines For Limiting Exposure To The Time-Varying Electric, Magnetic And Electromagnetic Fields (Up To 300 GHz)”. International Commission on Non-Ionizing Radiation Protection (1998年). 2014年6月6日時点のオリジナルよりアーカイブ。2013年12月12日閲覧。
^“Stringent Mobile Radiation Standards Come into Force from tomorrow New Mobile Handsets to comply with SAR Value of 1.6W/KG - Penalty, Random Checks Introduced for Enforcement”. Press Information Bureau, Government of India (2012年8月31日). 2013年12月22日閲覧。
^“無線設備規則”. 総務省 電波利用ホームページ. 2019年3月1日閲覧。
^ abFrey, Allan H (1962). “Human auditory system response to modulated electromagnetic energy”. Journal of Applied Physiology17 (4): 689–692. PMID 13895081. http://jap.physiology.org/content/17/4/689.abstract?sid=7c073ad2-6324-4b47-94e1-124dc0a5f154.
^Frey, Allan H (1998). “Headaches from cellular telephones: are they real and what are the implications?”. Environmental Health Perspectives (National Institute of Environmental Health Sciences) 106 (3): 101–103. doi:10.1289/ehp.98106101. PMC: 1533043. PMID 9441959. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1533043/.
^“Specific Absorption Rate (SAR) For Cell Phones: What It Means For You”. Federal Communications Commission. 2013年12月22日閲覧。
外部リンク
Specific Absorption Rate (SAR) for Cellular Telephones at the US Federal Communications Commission (FCC)
"Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Field" (Supplement C to OET Bulletin 65), June 2001; a detailed technical document about measuring SAR
Electromagnetic fields and public health at the World Health Organization (WHO)
"An Update on SAR Standards and the Basic Requirements for SAR Assessment" at ETS-Lindgren website, April 2005
Example of a detailed SAR report from the FCC web site (for an Apple iPod Touch 4th generation); hosted at 3rd party website
Manufacturers' SAR official websites
Apple
Motorola
Nokia
Samsung
Sony
[1]
FCC Regulations
OET Bulletin No. 56, "Questions and Answers About the Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields."
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…the original manufacturer guidelines, brain MRI is safe at <2 Tesla field strength and a specific absorption rate of <1.3 W/kg, conducted with a send and receive head coil, with the vagus nerve stimulation…
…gradient magnetic field of 720 G/cm or less; Maximum MRI system-reported, whole-body-averaged specific absorption rate (SAR) of 2W/kg (up to 3W/kg for the ADO devices) for 15 minutes of scanning; Image quality…